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1. Band Alignment and Photoresponse of LaFeO3 -Based Heterojunctions

Author: Yunwei Sheng, Mathieu Mirjolet, Mario Villa, Jaume Gàzquez, José Santiso, Andreas Klein, Jordi Fraxedas, and Josep Fontcuberta
Subjects: General Physics and Astronomy
Published: 2023
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2. Fermi energy, electrical conductivity, and the energy gap of NaNbO3

Author: Nicole Bein, Brigita Kmet, Tadej Rojac, Andreja Benčan Golob, Barbara Malič, Julian Moxter, Thorsten Schneider, Lovro Fulanovic, Maryam Azadeh, Till Frömling, Sonja Egert, Hongguang Wang, Peter van Aken, Jutta Schwarzkopf, and Andreas Klein
Subjects: Physics and Astronomy (miscellaneous), General Materials Science
Published: 2022
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3. Beam-target helicity asymmetry E in K0Λ and K0Σ0 photoproduction on the neutron

Author: P. Lenisa, M. Ungaro, D. G. Ireland, C. A. Meyer, R. Dupre, V. Crede, C.D. Bass, V. A. Nikonov, M. Battaglieri, P. Chatagnon, G. V. Fedotov, R. A. Montgomery, Ron L. Workman, R. Paremuzyan, R. A. Schumacher, C. S. Whisnant, K. P. Adhikari, A. Fradi, M. Osipenko, D. G. Jenkins, Nicholas M. Harrison, N. Markov, Martin K. Mayer, K. A. Griffioen, I. Zonta, I. J. D. MacGregor, A. Kim, H. Hakobyan, M. Khachatryan, D. Sokhan, H. S. Jo, Tim O'Connell, D. Marchand, S. Diehl, M. Bashkanov, B. McKinnon, A. I. Ostrovidov, K. Park, V. Mokeev, G. Khachatryan, L. Lanza, Eberhard Klempt, P. Collins, S. Niccolai, F. X. Girod, M. Contalbrigo, Sandra K. Johnston, P. Eugenio, T. Chetry, Volker D. Burkert, A. S. Biselli, Pawel Nadel-Turonski, M. Mirazita, J. Zhang, Rong Wang, J. W. Price, Alessandro Rizzo, S. Strauch, Iu. Skorodumina, C. Hanretty, George Davey Smith, M. Taiuti, C. Djalali, J. A. Tan, E. Golovatch, Y. G. Sharabian, M. Lowry, G. Charles, K. L. Giovanetti, I. Bedlinskiy, M. Rehfuss, K. Hicks, S. Adhikari, M. L. Kabir, M. Ehrhart, F. Sabatié, Andreas Klein, V. Laine, F. Cao, D. Adikaram, M. Guidal, W. Kim, Larry Weinstein, Z. Akbar, G. Rosner, P. Peng, C. Munoz Camacho, M. H. Wood, M. Hattawy, G. Niculescu, J. A. Fleming, I. I. Strakovsky, M. Holtrop, A. Filippi, A. D'Angelo, M. Ripani, Y. Ghandilyan, Carlos A. Salgado, B. A. Clary, A. M. Sandorfi, B. S. Ishkhanov, M. Khandaker, D. I. Sober, A. Deur, Hong Lu, Michael Paolone, D. Ho, S. Fegan, A. Celentano, R. W. Gothe, D. Heddle, Maxime Defurne, E. L. Isupov, W. Gohn, S. Boiarinov, R. De Vita, T. Kageya, L. El Fassi, N. K. Walford, R. G. Fersch, Frank Klein, P. L. Cole, Z. W. Zhao, Dustin Keller, G. Ciullo, J. P. Ball, Y. Prok, D. S. Carman, Nikos Sparveris, X. Wei, K. Hafidi, E. Voutier, A. Movsisyan, Yordanka Ilieva, L. Barion, V. P. Kubarovsky, D. Riser, A. El Alaoui, Nicholas Zachariou, O. Pogorelko, K. Livingston, H. Voskanyan, D. Protopopescu, W. J. Briscoe, E. Pasyuk, D. P. Watts, H. Egiyan, A. V. Sarantsev, and S. Chandavar
Subjects: Physics, Strange quark, 010308 nuclear & particles physics, media_common.quotation_subject, Nuclear Theory, Quark model, Hyperon, 01 natural sciences, Helicity, Asymmetry, Pseudoscalar meson, Nuclear physics, 13. Climate action, Isospin, 0103 physical sciences, Neutron, Nuclear Experiment, 010306 general physics, media_common
Abstract: We report the first measurements of the E beam-target helicity asymmetry for the γn→K0Λ and K0Σ0 channels in the energy range 1.70≤W≤2.34 GeV. The CLAS system at Jefferson Lab uses a circularly polarized photon beam and a target consisting of longitudinally polarized solid molecular hydrogen deuteride with low background contamination for the measurements. The multivariate analysis method boosted decision trees is used to isolate the reactions of interest. Comparisons with predictions from the KaonMAID, SAID, and Bonn-Gatchina models are presented. These results will help separate the isospin I=0 and I=1 photocoupling transition amplitudes in pseudoscalar meson photoproduction.
Published: 2018
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4. Exclusive photoproduction of π0 up to large values of Mandelstam variables s,t, and u with CLAS

Author: S. Adhikari, S. E. Kuhn, M. Hattawy, P. Eugenio, Taya Chetry, E. Golovatch, M. Taiuti, D. Lersch, M. L. Kabir, E. De Sanctis, Carlos A. Salgado, Michael Paolone, S. Procureur, D. I. Sober, D. Protopopescu, G. V. Fedotov, A. Roy, M. Ripani, M. Khachatryan, D. P. Weygand, R. Dupre, M. Battaglieri, Maxime Defurne, M. C. Kunkel, J. Ritman, F. Cao, M. Guidal, Michael Dugger, G. Gavalian, V. P. Kubarovsky, O. Pogorelko, D. I. Glazier, G. Niculescu, P. Lenisa, A. El Alaoui, Barry Ritchie, Iu. Skorodumina, I. Balossino, D. G. Ireland, V. Crede, Frank Klein, I. Bedlinskiy, K. A. Griffioen, R. De Vita, W. Gohn, V. Mokeev, M. Holtrop, L. Elouadrhiri, Y. G. Sharabian, Andreas Klein, Nicholas Zachariou, G. Mbianda Njencheu, W. Phelps, R. A. Schumacher, Dustin Keller, I. I. Strakovsky, A. Filippi, A. Deur, C. Djalali, R. A. Montgomery, K. Hafidi, V. Batourine, H. Avakian, J. A. Tan, L. Lanza, A. D'Angelo, D. P. Watts, D. G. Jenkins, H. Voskanyan, K. Livingston, F. Sabatié, H. Egiyan, M. Khandaker, S. Niccolai, J. Zhang, S. Bültmann, W. J. Briscoe, E. Pasyuk, Alessandro Rizzo, L. El Fassi, J. W. Price, C. E. Hyde, F. X. Girod, L. Guo, M. Ungaro, T. Mineeva, R. G. Fersch, Pawel Nadel-Turonski, P. L. Cole, Z. W. Zhao, K. Hicks, Laura Clark, W. Kim, K. Joo, S. Strauch, G. Charles, B. S. Ishkhanov, O. Cortes, G. Ciullo, E. L. Isupov, J. P. Ball, Y. Prok, D. S. Carman, D. Payette, M. Osipenko, S. Boiarinov, Nikos Sparveris, X. Wei, I. J. D. MacGregor, K. P. Adhikari, A. Kim, E. Voutier, A. Movsisyan, N. Dashyan, H. Hakobyan, S. Stepanyan, L. Barion, M. J. Amaryan, K. L. Giovanetti, Larry Weinstein, G. Khachatryan, S. Schadmand, William Brooks, G. Rosner, S. Ghosh, Y. Ghandilyan, P. V. Degtyarenko, A. Celentano, R. W. Gothe, M. Contalbrigo, C. Munoz Camacho, J. Poudel, B. McKinnon, J. M. Laget, Nicholas M. Harrison, Gerard Gilfoyle, D. Sokhan, A. Fradi, N. Markov, A. I. Ostrovidov, K. Park, G. R. Goldstein, Volker D. Burkert, and A. S. Biselli
Subjects: Quark, Quantum chromodynamics, Physics, Meson, 010308 nuclear & particles physics, Perturbative QCD, Parton, Mandelstam variables, Photon energy, 01 natural sciences, Nuclear physics, 0103 physical sciences, High Energy Physics::Experiment, Sum rule in quantum mechanics, 010306 general physics
Abstract: Exclusive photoproduction cross sections have been measured for the process γ p → p π 0 [ e + e − ( γ ) ] with the Dalitz decay final state using tagged photon energies in the range of E γ = 1.275 – 5.425 GeV. The complete angular distribution of the final state π 0 , for the entire photon energy range up to large values of t and u , has been measured for the first time. The data obtained show that the cross section d σ / d t , at mid to large angles, decreases with energy as s − 6.89 ± 0.26 . This is in agreement with the perturbative QCD quark counting rule prediction of s − 7 . Paradoxically, the size of angular distribution of measured cross sections is greatly underestimated by the QCD-based generalized parton distribution mechanism at highest available invariant energy s = 11 GeV 2 . At the same time, the Regge-exchange-based models for π 0 photoproduction are more consistent with experimental data.
Published: 2018
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5. Measurement of the beam asymmetry Σ and the target asymmetry T in the photoproduction of ω mesons off the proton using CLAS at Jefferson Laboratory

Author: William Brooks, George Davey Smith, R. A. Schumacher, A. El Alaoui, S. Stepanyan, J. Pierce, H. Y. Lu, P. Eugenio, G. Gavalian, I. Denisenko, N. Dashyan, Taya Chetry, M. Taiuti, A. Filippi, A. Fradi, D. P. Watts, K. A. Griffioen, Friedrich Klein, V. Crede, M. Khandaker, D. G. Meekins, Brian Raue, A. D'Angelo, A. V. Sarantsev, Yordanka Ilieva, Nicholas Zachariou, E. Pasyuk, V. Mokeev, V. Batourine, R. Paremuzyan, R. De Vita, N. Markov, L. Lanza, G. Rosner, E. Golovatch, K. Hicks, W. Kim, Sergey Kuleshov, M. Ripani, R. A. Montgomery, F. Sabatié, S. Niccolai, Carlos A. Salgado, C. D. Keith, Pawel Nadel-Turonski, D. G. Jenkins, Eberhard Klempt, B. A. Clary, J. Brock, Alessandro Rizzo, R. Dupre, M. Battaglieri, J. Zhang, C. Djalali, J. A. Tan, L. El Fassi, J. W. Price, S. Anefalos Pereira, K. Livingston, C. Hanretty, C. Carlin, M. Guidal, L. Guo, M. Ungaro, Gerard Gilfoyle, A. I. Ostrovidov, A. V. Anisovich, K. Park, G. Charles, G. Niculescu, V. A. Nikonov, G. Ciullo, J. P. Ball, B. Torayev, Y. Prok, F. X. Girod, M. E. McCracken, D. S. Carman, D. G. Ireland, M. Holtrop, K. Joo, I. Bedlinskiy, V. P. Kubarovsky, D. Riser, M. Osipenko, Andreas Klein, Nikos Sparveris, X. Wei, T. Mineeva, D. Sokhan, O. Pogorelko, S. Procureur, W. Gohn, A. Kim, Z. E. Meziani, W. Phelps, Volker D. Burkert, M. Bashkanov, A. S. Biselli, B. S. Ishkhanov, L. Elouadrhiri, K. L. Giovanetti, I. Balossino, S. Strauch, Michael Dugger, D. I. Sober, E. Voutier, I. I. Strakovsky, A. Movsisyan, B. McKinnon, Dustin Keller, S. Park, A. Deur, K. Hafidi, Iu. Skorodumina, Sylvester Joosten, S. Fegan, G. Khachatryan, P. L. Cole, Z. W. Zhao, E. Phelps, N. Gevorgyan, D. Protopopescu, W. J. Briscoe, C. Munoz Camacho, M. H. Wood, A. Celentano, R. W. Gothe, M. Contalbrigo, Z. Akbar, N. K. Walford, I. J. D. MacGregor, S. Adhikari, M. Hattawy, Martin K. Mayer, Y. G. Sharabian, C. Gleason, Barry Ritchie, P. Roy, C. A. Meyer, G. V. Fedotov, E. L. Isupov, S. Boiarinov, K. P. Adhikari, H. Hakobyan, and P. Lenisa
Subjects: Physics, Particle physics, Proton, Meson, 010308 nuclear & particles physics, Partial wave analysis, media_common.quotation_subject, Nuclear Theory, Bremsstrahlung, Observable, 7. Clean energy, 01 natural sciences, Resonance (particle physics), Asymmetry, Baryon, Nuclear physics, 13. Climate action, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, media_common
Abstract: The photoproduction of ω mesons off the proton has been studied in the reaction γp→pω using the CEBAF Large Acceptance Spectrometer (CLAS) and the frozen-spin target in Hall B at the Thomas Jefferson National Accelerator Facility. For the first time, the target asymmetry T has been measured in photoproduction from the decay ω→π+π-π0, using a transversely polarized target with energies ranging from just above the reaction threshold up to 2.8 GeV. Significant nonzero values are observed for these asymmetries, reaching about 30-40% in the third-resonance region. New measurements for the photon-beam asymmetry Σ are also presented, which agree well with previous CLAS results and extend the world database up to 2.1 GeV. These data and additional ω photoproduction observables from CLAS were included in a partial-wave analysis within the Bonn-Gatchina framework. Significant contributions from s-channel resonance production were found in addition to t-channel exchange processes.
Published: 2018
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6. Measurement of the helicity asymmetry E in ω→π+π−π0 photoproduction

Author: M. Contalbrigo, T. Mineeva, R. A. Schumacher, Z. Akbar, M. Khachatryan, V. Mokeev, Taya Chetry, A. V. Anisovich, G. Ciullo, J. P. Ball, Y. Prok, D. S. Carman, E. Golovatch, F. Cao, P. Roy, M. Guidal, B. S. Ishkhanov, K. Hicks, C. Gleason, Iu. Skorodumina, Nikos Sparveris, X. Wei, M. Holtrop, O. Cortes, K. P. Adhikari, C. D. Keith, E. L. Isupov, M. Ripani, Barry Ritchie, E. Voutier, Nicholas Zachariou, S. Stepanyan, Laura Clark, L. Guo, H. Egiyan, S. Boiarinov, G. Khachatryan, A. Movsisyan, I. J. D. MacGregor, E. De Sanctis, G. Charles, J. Brock, Sylvester Joosten, M. Hattawy, Carlos A. Salgado, A. Celentano, R. W. Gothe, A. V. Sarantsev, S. Park, M. Osipenko, F. Sabatié, W. J. Briscoe, I. I. Strakovsky, Y. G. Sharabian, S. Niccolai, M. Ungaro, D. I. Sober, A. I. Ostrovidov, K. Park, Michael Paolone, R. Dupre, M. Battaglieri, C. Munoz Camacho, A. Filippi, G. V. Fedotov, A. Deur, K. A. Griffioen, V. Crede, D. G. Ireland, W. Phelps, Lorenzo Zana, S. Adhikari, N. Dashyan, D. Protopopescu, Alessandro Rizzo, M. Garçon, Volker D. Burkert, B. McKinnon, W. K. Brooks, D. G. Jenkins, I. Bedlinskiy, V. A. Nikonov, Brian Raue, P. Nadel-Turonski, A. Fradi, F. X. Girod, W. Kim, I. Denisenko, V. Batourine, Michael Dugger, G. Rosner, N. Markov, R. Paremuzyan, S. Strauch, Andreas Klein, K. Livingston, W. Gohn, R. De Vita, C. Carlin, Nicholas M. Harrison, S. Anefalos Pereira, L. Lanza, D. Sokhan, A. Kim, C. Djalali, C. Hanretty, R. Fersch, H. Avakian, Eberhard Klempt, J. Zhang, H. Voskanyan, E. Pasyuk, J. W. Price, George Davey Smith, V. P. Kubarovsky, D. G. Meekins, A. D'Angelo, O. Pogorelko, Frank Klein, Dustin Keller, L. El Fassi, Michael Wood, K. Hafidi, P. L. Cole, Z. W. Zhao, P. Eugenio, M. Taiuti, N. Gevorgyan, D. Heddle, G. Hollis, Hrachya Hakobyan, M. J. Amaryan, K. L. Giovanetti, and M. Khandaker
Subjects: Physics, Meson, 010308 nuclear & particles physics, Partial wave analysis, Bremsstrahlung, Resonance, Observable, 01 natural sciences, Helicity, Nuclear physics, Pomeron, 0103 physical sciences, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: The double-polarization observable E was studied for the reaction γp → pω using the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B at the Thomas Jefferson National Accelerator Facility and the longitudinally polarized frozen-spin target (FROST). The observable was measured from the charged decay mode of the meson, ω → π+π−π0, using a circularly polarized tagged-photon beam with energies ranging from the ω threshold at 1.1 to 2.3 GeV. A partial-wave analysis within the Bonn-Gatchina framework found dominant contributions from the 3/2+ partial wave near threshold, which is identified with the subthreshold N(1720) 3/2+ nucleon resonance. To describe the entire data set, which consisted of ω differential cross sections and a large variety of polarization observables, further contributions from other nucleon resonances were found to be necessary. With respect to nonresonant mechanisms, π exchange in the t channel was found to remain small across the analyzed energy range, while Pomeron t-channel exchange gradually grew from the reaction threshold to dominate all other contributions above W ≈ 2 GeV.
Published: 2017
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7. Reversible metal-insulator transition of Ar-irradiatedLaAlO3/SrTiO3interfaces

Author: V. I. Sakharov, Paul Erhart, Yu. A. Boikov, Nikolina Tuzla, Pier Paolo Aurino, Tord Claeson, A. Kalabukhov, I. T. Serenkov, Eva Olsson, Andreas Klein, and Dag Winkler
Subjects: Argon, Materials science, Condensed matter physics, chemistry.chemical_element, Heterojunction, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Amorphous solid, Ion, Condensed Matter::Materials Science, Ion implantation, chemistry, Etching (microfabrication), Irradiation, Metal–insulator transition
Abstract: The conducting state of a quasi-two-dimensional electron gas (q2DEG), formed at the heterointerface between the two wide-bandgap insulators LaAlO3 (LAO) and SrTiO3, can be made completely insulating by low-energy, 150-eV, Ar+ irradiation. The metallic behavior of the interface can be recovered by high-temperature oxygen annealing. The electrical transport properties of the recovered q2DEG are exactly the same as before the irradiation. Microstructural investigations confirm that the transition is not due to physical etching or crystal lattice distortion of the LAO film below its critical thickness. They also reveal a correlation between electrical state, LAO film surface amorphization, and argon ion implantation. The experimental results are in agreement with density functional theory calculations of Ar implantation and migration in the LAO film. This suggests that the metal-insulator transition may be caused by charge trapping in the defect amorphous layer created during the ion irradiation.
Published: 2015
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8. Publisher's Note: Exclusiveπ0electroproduction atW>2GeV with CLAS [Phys. Rev. C 90, 025205 (2014)]

Author: George Davey Smith, N. A. Baltzell, D. Doughty, M. Khandaker, A. Simonyan, J. P. Ball, A. D'Angelo, Y. Prok, D. S. Carman, I. Zonta, H. Moutarde, K. L. Giovanetti, Larry Weinstein, X. Wei, H. Y. Lu, E. De Sanctis, V. P. Kubarovsky, M. Contalbrigo, Sergey Kuleshov, L. El Fassi, O. Pogorelko, D. I. Sober, D. Protopopescu, M. Garçon, E. Voutier, A. Movsisyan, N. Dashyan, Y. G. Sharabian, S. Chandavar, Frank Klein, A. V. Vlassov, F. X. Girod, D. G. Ireland, Dustin Keller, K. Livingston, C. Munoz Camacho, R. De Vita, K. P. Adhikari, V. Crede, Andrew Puckett, Lorenzo Zana, Martin K. Mayer, K. Hafidi, R. Dupre, S. Anefalos Pereira, V. Sytnik, M. Battaglieri, P. L. Cole, Z. W. Zhao, H. Hakobyan, H. S. Jo, B. McKinnon, S. Strauch, W. Kim, S. Niccolai, H. Avakian, P. Nadel-Turonski, B. Guegan, R. A. Montgomery, M. Mirazita, I. Niculescu, M. Yurov, E. Phelps, Diane Schott, H. Voskanyan, N. Gevorgyan, S. Fegan, S. Koirala, A. I. Ostrovidov, K. Park, G. V. Fedotov, W. J. Briscoe, E. Pasyuk, P. Roy, C. Djalali, A. Celentano, R. W. Gothe, M. Ripani, Volker D. Burkert, M. Guidal, A. S. Biselli, D. P. Watts, H. Egiyan, Nicholas M. Harrison, A. El Alaoui, L. Colaneri, Gerard Gilfoyle, D. Sokhan, D. G. Jenkins, W. I. Levine, M. Holtrop, Nicholas Zachariou, N. Markov, R. A. Schumacher, S. E. Kuhn, M. Hattawy, S. Pisano, Luciano Pappalardo, O. Cortes, I. Bedlinskiy, J. A. Fleming, J. Bono, K. A. Griffioen, E. L. Isupov, N. K. Walford, Andreas Klein, J. J. Phillips, Ye Tian, S. Park, P. Eugenio, Carlos A. Salgado, S. Boiarinov, P. Rossi, W. Tang, Y. Ghandilyan, Barry Ritchie, B. S. Ishkhanov, M. Osipenko, T. A. Forest, S. Stepanyan, B. Garillon, S. Procureur, P. Stoler, A. Kim, E. Seder, K. Hicks, William Brooks, I. J. D. MacGregor, W. Phelps, G. Gavalian, V. Mokeev, I. Senderovich, Alessandro Rizzo, E. Golovatch, L. Elouadrhiri, A. Deur, J. Zhang, J. W. Price, L. Guo, M. Ungaro, K. Joo, V. Batourine, F. Sabatié, C. I. Moody, P. Lenisa, and Brian Raue
Subjects: Physics, Nuclear physics, Nuclear and High Energy Physics, Meson production
Published: 2014
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9. Publisher's Note: Beam asymmetryΣforπ+andπ0photoproduction on the proton for photon energies from 1.102 to 1.862 GeV [Phys. Rev. C88, 065203 (2013)]

Author: L. Elouadrhiri, N. A. Baltzell, I. I. Strakovsky, C. S. Nepali, George Davey Smith, A. Deur, M. Contalbrigo, R. Paremuzyan, S. Fegan, D. Adikaram, M. Guidal, F. X. Girod, E. De Sanctis, A. D'Angelo, V. Mokeev, G. Niculescu, M. Khandaker, W. Tang, M. Aghasyan, M. Osipenko, Nicholas M. Harrison, Gerard Gilfoyle, M. Holtrop, D. I. Sober, A. El Alaoui, Nicholas Zachariou, L. El Fassi, D. Martinez, I. J. D. MacGregor, S. Park, D. Sokhan, S. Strauch, N. Dashyan, Luciano Pappalardo, P. Nadel-Turonski, P. Rossi, D. Rimal, I. Zonta, C. Djalali, A. Celentano, R. W. Gothe, D. P. Watts, W. Gohn, H. Y. Lu, S. Koirala, H. Egiyan, M. J. Amaryan, K. Livingston, Frank Klein, D. G. Ireland, Dustin Keller, Yordanka Ilieva, Diane Schott, E. Munevar, A. I. Ostrovidov, K. Park, R. De Vita, B. S. Ishkhanov, Michael Dugger, Sergey Kuleshov, Yakov I. Azimov, Brian Raue, H. Moutarde, V. Crede, E. Golovatch, A. Kubarovsky, K. A. Griffioen, N. K. Walford, I. Niculescu, N. Guler, K. L. Giovanetti, J. J. Phillips, K. Hafidi, S. Anefalos Pereira, R. A. Montgomery, P. Stoler, Ron L. Workman, V. Batourine, D. Doughty, G. Rosner, P. L. Cole, Z. W. Zhao, Volker D. Burkert, A. S. Biselli, R. A. Schumacher, S. Niccolai, D. Heddle, J. P. Ball, Y. Prok, D. S. Carman, F. Sabatié, K. Hicks, C. Hanretty, J. Zhang, S. Chandavar, S. Tkachenko, T. Mineeva, D. Protopopescu, J. W. Price, H. Avakian, P. Peng, B. Torayev, S. Pozdniakov, I. Senderovich, Alessandro Rizzo, E. Voutier, L. Guo, M. Ungaro, C. Munoz Camacho, S. Stepanyan, I. Bedlinskiy, Andreas Klein, M. Ripani, A. Kim, B. McKinnon, H. Voskanyan, K. Joo, Carlos A. Salgado, M. Mirazita, E. Phelps, W. J. Briscoe, E. Pasyuk, N. Gevorgyan, S. Procureur, S. Pisano, R. Dupre, M. Battaglieri, J. A. Fleming, V. P. Kubarovsky, P. Collins, O. Pogorelko, S. Lewis, Martin K. Mayer, M. S. Saini, J. T. Goetz, H. Seraydaryan, Y. G. Sharabian, P. Eugenio, M. Taiuti, D. Ho, E. Seder, Barry Ritchie, O. Cortes, E. L. Isupov, Ye Tian, S. Boiarinov, G. V. Fedotov, D. P. Weygand, K. P. Adhikari, Lorenzo Zana, H. Hakobyan, H. S. Jo, and W. Kim
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Meson production, Photon, Proton, Partial wave analysis, media_common.quotation_subject, Asymmetry, Beam (structure), media_common
Published: 2014
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10. Electronically Decoupled Films of InSe Prepared by van der Waals Epitaxy: Localized and Delocalized Valence States

Author: C. Pettenkofer, Rudy Schlaf, Andreas Klein, Wolfram Jaegermann, and O. Lang
Subjects: Materials science, Valence (chemistry), business.industry, General Physics and Astronomy, Self-assembled monolayer, Molecular physics, Delocalized electron, Semiconductor, Highly oriented pyrolytic graphite, X-ray photoelectron spectroscopy, Monolayer, Atomic physics, Electronic band structure, business
Abstract: Submonolayer to several monolayer thick films of the layered semiconductor InSe were deposited on highly oriented pyrolytic graphite by van der Waals epitaxy and probed by energy dependent angle resolved photoelectron spectroscopy. The layers show a transition from two-dimensional bands with atomiclike states to molecularlike states localized along the $c$ direction normal to the surface. The extended band structure showing band dispersion was observed for thicker films.
Published: 1998
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11. Influence of orbital contributions to the valence band alignment of Bi2O3, Fe2O3, BiFeO3, and Bi0.5Na0.5TiO3

Author: Karsten Albe, Klaus Ellmer, Melanie Gröting, Lucian Pintilie, Andreas Klein, Klaus Reichmann, Jan Morasch, Lichao Jia, Michael Naderer, Christina Chirila, and Shunyi Li
Subjects: Crystallography, Materials science, Band gap, Direct and indirect band gaps, Electron hole, Atomic physics, Condensed Matter Physics, Valence electron, Electronic band structure, Lone pair, Quasi Fermi level, Semimetal, Electronic, Optical and Magnetic Materials
Abstract: The formation of an interface between Bi${}_{2}$O${}_{3}$, Fe${}_{2}$O${}_{3}$, BiFeO${}_{3}$, Bi${}_{0.5}$Na${}_{0.5}$TiO${}_{3}$, and the high work function metallic RuO${}_{2}$ is studied using photoelectron spectroscopy with in situ RuO${}_{2}$ deposition. Schottky barrier heights are derived and the valence band maximum energies of the studied materials are aligned with respect to each other as well as to other functional oxides like SrTiO${}_{3}$ and PbTiO${}_{3}$. The energy band alignment follows systematic trends compared to a large number of oxides, and can be understood in terms of the contribution of Fe $3d$ and Bi $6s/6p$ (lone pair) orbitals to electronic states near the valence band maximum. The results indicate that the valence band maxima are largely determined by the local environment of the cations, which allows to estimate valence band maximum energies of oxides with multiple cations from those of their parent binary compounds. The high valence band maximum of BiFeO${}_{3}$ is consistent with reported $p$-type conduction of acceptor doped material, while the high conduction band minimum makes $n$-type conduction unlikely.
Published: 2013
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12. Publisher’s Note: Measurement of the NeutronF2Structure Function via Spectator Tagging with CLAS [Phys. Rev. Lett.108, 142001 (2012)]

Author: C. E. Hyde, D. G. Ireland, V. Crede, D. Protopopescu, S. Pozdniakov, H. C. Fenker, D. Adikaram, M. Guidal, Nicholas Kvaltine, G. Niculescu, P. Stoler, Wolodymyr Melnitchouk, G. V. Fedotov, N. Kalantarians, B. Dey, K. Hicks, A. Celentano, R. W. Gothe, M. J. Amaryan, H. Avakian, M. Holtrop, D. P. Weygand, E. De Sanctis, A. Daniel, A. El Alaoui, E. L. Isupov, M. Aghasyan, Luciano Pappalardo, B. Guegan, D. I. Sober, H. Moutarde, M. Contalbrigo, W. Kim, G. Charles, M. Ripani, S. Fegan, K. L. Giovanetti, C. E. Keppel, S. Bültmann, E. Seder, W. J. Briscoe, E. Pasyuk, Larry Weinstein, D. Rimal, Alexei V. Klimenko, D. Doughty, P. Khetarpal, P. E. Bosted, Carlos A. Salgado, Andreas Klein, K. Livingston, M. Ispiryan, Michael Vineyard, D. Heddle, K. P. Adhikari, S. Park, Brian Raue, N. Baillie, Y. Prok, D. S. Carman, B. Zhao, Lorenzo Zana, N. Guler, P. Rossi, H. S. Jo, B. McKinnon, W. Tang, S. E. Kuhn, P. Eugenio, M. Taiuti, R. De Vita, E. Voutier, M. Osipenko, N. Dashyan, D. Branford, V. P. Kubarovsky, M. Khandaker, F. Sabatié, S. S. Jawalkar, S. Niccolai, M. Gabrielyan, N. Gevorgyan, Frank Klein, I. J. D. MacGregor, Sergey Kuleshov, Yordanka Ilieva, M. Anghinolfi, S. Tkachenko, Y. G. Sharabian, S. Anefalos Pereira, Michael Wood, E. V. Hungerford, K. Hafidi, Gerard Gilfoyle, G. Ricco, F. X. Girod, D. Sokhan, M. S. Saini, T. Mineeva, M. E. Christy, Diane Schott, A. I. Ostrovidov, K. Park, Hovhannes Baghdasaryan, S. Strauch, Volker D. Burkert, A. S. Biselli, J. Domingo, A. Fradi, S. Pisano, B. Morrison, C. Djalali, K. A. Griffioen, Dipangkar Dutta, L. Guo, M. Ungaro, J. Arrington, R. A. Schumacher, L. Graham, S. S. Stepanyan, R. Dupre, M. Battaglieri, S. Stepanyan, William Brooks, Rolf Ent, G. E. Dodge, H. Y. Lu, S. Procureur, I. Niculescu, A. Kim, J. Zhang, G. Rosner, Y. Mao, S. Chandavar, J. W. Price, A. Ni, V. Tvaskis, D. P. Watts, H. Egiyan, P. Nadel-Turonski, N. Markov, E. Munevar, P. M. King, E. Golovatch, W. Gohn, L. Elouadrhiri, A. Deur, P. L. Cole, A. D'Angelo, and L. El Fassi
Subjects: Physics, Nuclear physics, Structure function, General Physics and Astronomy, Neutron
Published: 2012
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13. Role of copper interstitials in CuInSe2: First-principles calculations

Author: Karsten Albe, Johan Pohl, and Andreas Klein
Subjects: Materials science, chemistry, Condensed matter physics, Chemical physics, Interstitial diffusion, chemistry.chemical_element, Density functional theory, Diffusion (business), Condensed Matter Physics, Copper, Electronic, Optical and Magnetic Materials
Abstract: Formation enthalpies and migration barriers of copper interstitials and Frenkel pairs in CuInSe${}_{2}$ (CIS) are determined by first-principles calculations within density functional theory using the nonlocal screened exchange Heyd-Scuseria-Ernzerhof (HSE06) functional. Interstitials occur on four symmetrically inequivalent sites with formation enthalpies of 0.17--0.38 eV, which are much lower than previously reported values based on local approximations. A direct interstitial and indirect interstitialcy diffusion mechanism with migration barriers as low as 0.22 and 0.34 eV are identified. The results provide evidence that the fast interstitial diffusion of copper is important for understanding metastabilities, Fermi-level pinning at interfaces, electric-field-induced creation of $p$-$n$ junctions, and widely varying experimentally measured diffusion coefficients in CIS devices.
Published: 2011
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14. PbTiO3/SrTiO3interface: Energy band alignment and its relation to the limits of Fermi level variation

Author: Andreas Klein, Robert Schafranek, Wenbin Wu, Feng Chen, and Shunyi Li
Subjects: Materials science, Condensed matter physics, Band gap, Doping, Fermi level, Heterojunction, Condensed Matter Physics, Semimetal, Electronic, Optical and Magnetic Materials, symbols.namesake, Band bending, symbols, Atomic physics, Electronic band structure, Quasi Fermi level
Abstract: The interface formation between PbTiO3 and SrTiO3 has been studied by in situ photoelectron spectroscopy. A valence band offset of 1.1±0.1 eV, corresponding to a conduction band offset of 1.3±0.1 eV, is determined. These values are in good agreement with the band offsets estimated from measured ionization potentials of SrTiO3 and PbTiO3 surfaces. The observed band offsets are also in line with a ~1.1 eV difference in barrier heights of PbTiO3 in contact with different electrode materials as compared to barrier heights of SrTiO3 with the same electrode materials. The results indicate that the band alignment is not strongly affected by Fermi level pinning and that the barrier heights are transitive. The limits of Fermi level variation observed from a number of thin films prepared on different substrates with different conditions are the same for both materials when these are aligned following the experimentally determined band offsets. By further comparing electrical conductivities reported for SrTiO3 and PbTiO3, it is suggested that the range of Fermi level position in the bulk of these materials, which corresponds to the range of observed conductivities, is comparable to the range of Fermi level position at interfaces with different contact materials. In particular the possibly low barrier height for electron injection into SrTiO3 is consistent with the metallic conduction of donor doped or reduced SrTiO3, while barrier heights ≳1 eV for PbTiO3 are consistent with the high resistivity even at high doping concentrations. The variation of barrier heights at interfaces therefore provides access to the range of possible Fermi level positions in the interior of any, including insulating, materials, which is relevant for understanding defect properties.
Published: 2011
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15. Coherent photoproduction ofπ+fromHe3

Author: C. E. Hyde, H. Moutarde, K. L. Giovanetti, Larry Weinstein, William Brooks, P. Khetarpal, B. McKinnon, C. Djalali, E. S. Smith, B. Guegan, G. Rosner, K. A. Griffioen, S. Fegan, Barry Ritchie, W. J. Briscoe, E. Pasyuk, B. L. Berman, S. Park, R. W. Gothe, Y. Perrin, H. Y. Lu, D. Branford, Frank Klein, W. Gohn, Sergey Kuleshov, M. Mirazita, F. X. Girod, Dustin Keller, N. Dashyan, J. McAndrew, P. L. Cole, Z. W. Zhao, George Davey Smith, I. Niculescu, P. Collins, D. G. Ireland, V. Crede, K. Hafidi, A. Deur, Yordanka Ilieva, W. Tang, M. Taiuti, S. Strauch, C. E. Taylor, A. D'Angelo, R. A. Schumacher, M. Osipenko, B. Morrison, D. P. Weygand, L. Casey, V. Batourine, L. Graham, D. Adikaram, L. El Fassi, P. Stoler, G. Niculescu, I. J. D. MacGregor, V. P. Kubarovsky, A. M. Micherdzinska, F. Sabatié, B. Zhao, M. Holtrop, J. P. Ball, R. Dupre, M. Battaglieri, B. Dey, S. Stepanyan, A. Daniel, D. S. Carman, C. Hanretty, Diane Schott, E. Voutier, R. Suleiman, A. Kim, D. J. Tedeschi, A. I. Ostrovidov, I. Bedlinskiy, P. Konczykowski, Andreas Klein, S. Procureur, D. P. Watts, V. Kuznetsov, H. Egiyan, K. Park, E. Munevar, Pawel Nadel-Turonski, S. Niccolai, Rakhsha Nasseripour, M. H. Wood, R. Paremuzyan, A. Ni, Gerard Gilfoyle, Volker D. Burkert, A. S. Biselli, D. Sokhan, A. El Alaoui, B. Vernarsky, B. Moreno, K. Livingston, R. Dickson, A. Fradi, S. Pisano, D. Protopopescu, S. Pozdniakov, Nicholas Kvaltine, D. Doughty, D. Heddle, M. Khandaker, M. Gabrielyan, M. Anghinolfi, H. Seraydaryan, S. Tkachenko, Y. G. Sharabian, M. Ripani, Carlos A. Salgado, Paolo Rossi, Martin K. Mayer, Michael Paolone, M. S. Saini, J. T. Goetz, S. E. Kuhn, E. De Sanctis, D. I. Sober, R. De Vita, S. Anefalos Pereira, M. Ungaro, S. S. Stepanyan, J. W. Price, K. P. Adhikari, H. Hakobyan, K. Moriya, E. L. Isupov, Michael Vineyard, and W. Kim
Subjects: Physics, Nuclear physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, 0103 physical sciences, 010306 general physics, 01 natural sciences
Published: 2011
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16. Laterally inhomogeneous surface-potential distribution and photovoltage at clustered In/WSe2(0001) interfaces

Author: C. Pettenkofer, Wolfram Jaegermann, Andreas Klein, and Rudy Schlaf
Subjects: Materials science, Photoemission spectroscopy, business.industry, Scanning electron microscope, chemistry.chemical_element, Substrate (electronics), Molecular physics, law.invention, Optics, Band bending, Electron diffraction, chemistry, law, Scanning tunneling microscope, business, Spectroscopy, Indium
Abstract: Small increments of indium were evaporated at 300 and 100 K onto the van der Waals (0001) surface of p-type ${\mathrm{WSe}}_{2}$ crystals. The interface formation was investigated in vacuo with x-ray photoemission spectroscopy, ultraviolet photoemisson spectroscopy, soft-x-ray photoemission spectroscopy, and low-energy electron diffraction. Additional scanning tunneling microscopy (STM), scanning electron microscopy (SEM), and microprobe measurements were performed ex situ. For deposition at 300 K a nonreactive interface is formed and the indium layer grows in the Volmer-Weber growth mode. The size and distribution of the In clusters for specific coverages were determined ex situ by STM and SEM. The band bending of 0.55 eV, as determined from binding-energy shifts of the substrate emissions, is far below the expected Schottky-limit value of 1.1 eV. The observed surface-photovoltage (SPV) shifts of the substrate emission lines are smaller (up to 0.2 eV) than those from the adsorbate lines. The maximum adsorbate SPV shift of 0.6 eV at 150 K exceeds the measured band bending, indicating that the band bending beneath the In clusters must be larger than between them. At a sample temperature of 100 K, In forms atomically flat layers (Frank--van der Merwe growth) allowing the determination of the actual band bending of 0.9--1.0 eV below the In-covered surface. For these conditions, the SPV is only 0.1 eV due to an electrical leakage current. During warmup to 300 K, a transition to the clustered interface occurs. For this interface, the band bending below the indium clusters could also be determined from temperature-dependent SPV measurements. The determined barrier height of 1.04 eV is in good agreement with the value measured at the unclustered interface.
Published: 1993
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17. Probing Quark-Gluon Interactions with Transverse Polarized Scattering

Author: L. G. Tang, D. McNulty, C. Yan, R. Asaturyan, Y. Prok, D. G. Crabb, P. McKee, L. Gan, J. Roche, Rolf Ent, M. Khandaker, C. Carasco, P. E. Bosted, J. Reinhold, D. G. Meekins, L. Coman, L. Cole, J. A. Dunne, H. Mkrtchyan, Y. Liang, Brian Raue, S. Stepanyan, J. Yun, Dinko Pocanic, W. F. Vulcan, D. Kiselev, K. Normand, R. D. Carlini, Karl Slifer, B. E. Norum, J. P. Chen, Ingo Sick, D. Gaskell, R. A. Lindgren, Andreas Klein, G. Testa, L. Yuan, A. Ahmidouch, M. Elaasar, J. Jourdan, F. R. Wesselmann, M. K. Jones, F. Bloch, B. Hu, I. Niculescu, Geoffrey Smith, Glen A. Warren, A. Aghalaryan, M. Zeier, Rakhsha Nasseripour, L. H. Kramer, O. Rondon, K. Wang, J. Cha, H. C. Fenker, S. Danagoulian, J. Gomez, J. Lichtenstadt, M. E. Christy, N. Savvinov, H. Zhu, Curtis Smith, Donal Day, S. Tajima, C. D. Keith, S. A. Wood, W.U. Boeglin, D. J. Mack, M. L. Seely, B. Sawatzky, C. E. Keppel, and Emil Frlez
Subjects: Physics, Quark, Quantum chromodynamics, Particle physics, Nuclear Theory, High Energy Physics::Phenomenology, Momentum transfer, FOS: Physical sciences, General Physics and Astronomy, Inelastic scattering, Matrix (mathematics), Isospin, High Energy Physics::Experiment, Sum rule in quantum mechanics, Nuclear Experiment (nucl-ex), Twist, Nuclear Experiment
Abstract: We have extracted QCD matrix elements from our data on double polarized inelastic scattering of electrons on nuclei. We find the higher twist matrix element \tilde{d_2}, which arises strictly from quark- gluon interactions, to be unambiguously non zero. The data also reveal an isospin dependence of higher twist effects if we assume that the Burkhardt-Cottingham Sum rule is valid. The fundamental Bjorken sum rule obtained from the a0 matrix element is satisfied at our low momentum transfer., formerly "Nachtmann Moments of the Proton and Deuteron Spin Structure Functions"
Published: 2010
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18. Electronic structure ofIn2O3and Sn-dopedIn2O3by hard x-ray photoemission spectroscopy

Author: G. Panaccione, Piero Torelli, Su-Huai Wei, V. Krishnakumar, Aron Walsh, J.L.F. da Silva, Andreas Klein, David J. Payne, Christoph Körber, and Russell G. Egdell
Subjects: Materials science, Valence (chemistry), Photoemission spectroscopy, Excited state, Inverse photoemission spectroscopy, Angle-resolved photoemission spectroscopy, Electronic structure, Atomic physics, Condensed Matter Physics, Spectroscopy, Spectral line, Electronic, Optical and Magnetic Materials
Abstract: The valence and core levels of In(2)O(3) and Sn-doped In(2)O(3) have been studied by hard x-ray photoemission spectroscopy (hv = 6000 eV) and by conventional Al K alpha (hv = 1486.6 eV) x-ray photoemission spectroscopy. The experimental spectra are compared with density-functional theory calculations. It is shown that structure deriving from electronic levels with significant In or Sn 5s character is selectively enhanced under 6000 eV excitation. This allows us to infer that conduction band states in Sn-doped samples and states at the bottom of the valence band both contain a pronounced In 5s contribution. The In 3d core line measured at hv = 1486.6 eV for both undoped and Sn-doped In(2)O(3) display an asymmetric lineshape, and may be fitted with two components associated with screened and unscreened final states. The In 3d core line spectra excited at hv = 6000 eV for the Sn-doped samples display pronounced shoulders and demand a fit with two components. The In 3d core line spectrum for the undoped sample can also be fitted with two components, although the relative intensity of the component associated with the screened final state is low, compared to excitation at 1486.6 eV. These results are consistent with a high concentration of carriers confined close to the surface of nominally undoped In(2)O(3). This conclusion is in accord with the fact that a conduction band feature observed for undoped In(2)O(3) in Al K alpha x-ray photoemission is much weaker than expected in hard x-ray photoemission.
Published: 2010
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19. Charged pion form factor betweenQ2=0.60and2.45 GeV2. II. Determination of, and results for, the pion form factor

Author: C. E. Keppel, D. J. Margaziotis, L. M. Qin, S. Vidakovic, John C. Mitchell, B. Zihlmann, T. Eden, V. Tadevosyan, Y. Okayasu, J. Arrington, D. H. Potterveld, J. Roche, Toshinobu Miyoshi, D. van Westrum, B. Mueller, K. A. Aniol, G. Niculescu, E. J. Brash, S. A. Wood, Ketevi Assamagan, K. Vansyoc, P. H. Kim, W. Zhao, D. McKee, H. C. Fenker, W.U. Boeglin, C. S. Armstrong, D. J. Mack, A. Matsumura, Stephen Avery, E. J. Beise, H. E. Jackson, D. Pitz, C. Xu, G. J. Lolos, A. J. Sarty, C. Yan, Andreas Klein, Jin Liu, M. E. Christy, P. E. Reimer, X. Zheng, I. K. Shin, J. Reinhold, E. F. Gibson, W. F. Vulcan, W. Hinton, S. Stepanyan, P. G. Roos, Ronald Gilman, C. C. Chang, R. van der Meer, D. Abbott, D. Gaskell, M. K. Jones, I. Niculescu, C. F. Perdrisat, Brynle Barrett, V. Kovaltchouk, H. Mkrtchyan, V. Tvaskis, A. F. Lung, Lubomir Pentchev, H. Anklin, Oliver Keith Baker, Geoffrey Smith, Pete Markowitz, Rolf Ent, Glen A. Warren, K. Gustafsson, M. Liang, C. Bochna, J. Volmer, G. M. Huber, P. M. King, D. Koltenuk, H. P. Blok, J. A. Dunne, L. G. Tang, V. A. Punjabi, D. G. Meekins, S. Jin, W. Kim, N. S. Chant, H. Breuer, Tanja Horn, and R. J. Holt
Subjects: Nuclear reaction, Physics, Nuclear and High Energy Physics, Particle physics, Bethe–Salpeter equation, 010308 nuclear & particles physics, Hadron, Lattice field theory, Magnetic monopole, Form factor (quantum field theory), Sigma, Particle accelerator, 7. Clean energy, 01 natural sciences, Charged particle, law.invention, Nuclear physics, Pion, law, Charge radius, 0103 physical sciences, Neutron, Invariant mass, Nucleon, 010306 general physics
Abstract: Cross sections for the reaction {sup 1}H(e,e'{Pi}{sup +})n were measured in Hall C at Thomas Jefferson National Accelerator Facility (JLab) using the high-intensity Continuous Electron Beam Accelerator Facility (CEBAF) to determine the charged pion form factor. Data were taken for central four-momentum transfers ranging from Q{sup 2} = 0.60 to 2.45 GeV{sup 2} at an invariant mass of the virtual photon-nucleon system of W = 1.95 and 2.22 GeV. The measured cross sections were separated into the four structure functions {sigma}{sub L},{sigma}{sub T}, {sigma}{sub LT}, and {sigma}{sub TT}. The various parts of the experimental setup and the analysis steps are described in detail, including the calibrations and systematic studies, which were needed to obtain high-precision results. The different types of systematic uncertainties are also discussed. The results for the separated cross sections as a function of the Mandelstam variable t at the different values of Q{sup 2} are presented. Some global features of the data are discussed, and the data are compared with the results of some model calculations for the reaction {sup 1}H(e,e'{Pi}{sup +})n.
Published: 2008
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20. Nature of the Band Gap ofIn2O3Revealed by First-Principles Calculations and X-Ray Spectroscopy

Author: David J. Payne, Christoph Körber, Russell G. Egdell, Andreas Klein, G. Panaccione, Alex Demasi, Juarez L. F. Da Silva, Piero Torelli, A. Bourlange, Kevin E. Smith, Louis F. J. Piper, Aron Walsh, and Su-Huai Wei
Subjects: Physics, National Synchrotron Light Source, Dipole, X-ray spectroscopy, Valence (chemistry), Band gap, General Physics and Astronomy, Direct and indirect band gaps, Atomic physics, Semimetal, Quasi Fermi level
Abstract: Bulk and surface sensitive x-ray spectroscopic techniques are applied in tandem to show that the valence band edge for In2O3 is found significantly closer to the bottom of the conduction band than expected on the basis of the widely quoted bulk band gap of 3.75 eV. First-principles theory shows that the upper valence bands of In2O3 exhibit a small dispersion and the conduction band minimum is positioned at Gamma. However, direct optical transitions give a minimal dipole intensity until 0.8 eV below the valence band maximum. The results set an upper limit on the fundamental band gap of 2.9 eV.
Published: 2008
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21. Changes in Electronic Structure and Chemical Bonding upon Crystallization of the Phase Change MaterialGeSb2Te4

Author: B. Späth, Alexander V. Kolobov, Andreas Klein, C. Steimer, Matthias Wuttig, Henning Dieker, and Paul Fons
Subjects: Crystallography, Materials science, Chemical bond, X-ray photoelectron spectroscopy, law, Chemical structure, Phase (matter), General Physics and Astronomy, Electronic structure, Crystallization, Electron spectroscopy, Amorphous solid, law.invention
Abstract: High-resolution photoelectron spectroscopy of in situ prepared films of ${\mathrm{GeSb}}_{2}{\mathrm{Te}}_{4}$ reveals significant differences in electronic and chemical structure between the amorphous and the crystalline phase. Evidence for two different chemical environments of Ge and Sb in the amorphous structure is found. This observation can explain the pronounced property contrast between both phases and provides new insight into the formation of the amorphous state.
Published: 2008
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22. Search for Medium Modifications of theρMeson

Author: S. A. Morrow, C. Djalali, C. Hanretty, A.V. Stavinsky, P. Ambrozewicz, D. J. Tedeschi, Baile Zhang, M. J. Amaryan, H. Juengst, R. A. Miskimen, B. McKinnon, M. MacCormick, Shifeng Chen, I. Bedlinskiy, Carlos A. Salgado, I. Hleiqawi, Andreas Klein, Ji Li, S. L. Careccia, D. Branford, L. Casey, B. B. Niczyporuk, N. Pivnyuk, Nikolay Shvedunov, M. Mirazita, J. M. Laget, K. L. Giovanetti, P. Collins, E. L. Isupov, N. Markov, J. Salamanca, Mark Richard James Williams, J. W C McNabb, Larry Weinstein, J. T. Goetz, S. Boiarinov, K. A. Griffioen, B. M. Preedom, S. McAleer, C. E. Hyde-Wright, J. P. Cummings, S. Niccolai, L. Elouadrhiri, S. Mehrabyan, H. Denizli, F. X. Girod, L. Blaszczyk, R. J. Feuerbach, Lorenzo Zana, J. Hardie, E. De Sanctis, Jens H. Kuhn, I. I. Strakovsky, A. I. Ostrovidov, K. Park, R. A. Schumacher, N. A. Baltzell, M. Khandaker, Dinko Pocanic, D. G. Ireland, V. Crede, Sergey Kuleshov, J. P. Santoro, M. Bektasoglu, H. Hakobyan, Federico Ronchetti, H. S. Jo, G. Riccardi, P. Muehlich, A. Deur, M. Kossov, Gerald Feldman, Volker D. Burkert, A. S. Biselli, S. E. Kuhn, J. R. Calarco, M. Guidal, Z. Krahn, L. C. Smith, E. Munevar, G. Ricco, D. I. Sober, S. Strauch, Rakhsha Nasseripour, K. Moriya, L. Todor, D. Doughty, C. Butuceanu, D. Protopopescu, N. Dashyan, G. Niculescu, M. Holtrop, N. Baillie, Mestayer, M. Battaglieri, B. S. Ishkhanov, S. Pozdniakov, M. Garçon, P. Eugenio, D. P. Watts, H. Egiyan, M. Taiuti, J. D. Kellie, R. C. Minehart, C. A. Meyer, B. Carnahan, S. Tkachenko, C. I O Gordon, F. Sabatié, V. Sapunenko, Laird Kramer, R. Bradford, B. A. Mecking, A. V. Vlassov, J. Langheinrich, G. V. Fedotov, N. Kalantarians, N. Benmouna, M. Ripani, M. Nozar, Yordanka Ilieva, Michael Vineyard, R. De Vita, Gerard Gilfoyle, M. Anghinolfi, Ulrich Mosel, J. J. Melone, Brian Raue, K. Livingston, James Mueller, D. P. Weygand, D. Sokhan, Cynthia Marie Hadjidakis, E. S. Smith, Maryam Moteabbed, M. R. Niroula, Alexei V. Klimenko, S. Anefalos Pereira, D. G. Jenkins, G. S. Mutchler, Michael Dugger, H. O. Funsten, Y. G. Sharabian, K. V. Dharmawardane, E. Wolin, B. L. Berman, S. Stepanyan, L. C. Dennis, R. Dickson, Sylvain Bouchigny, Barry Ritchie, J. P. Ball, Y. Prok, D. S. Carman, P. Rossi, C. Paterson, D. G. Crabb, J. Pierce, H. Avakian, P. Mattione, D. Sharov, N. Guler, G. E. Dodge, H. Y. Lu, P. V. Degtyarenko, S. Barrow, I. Niculescu, D. Lawrence, R. De Masi, P. Coltharp, William Brooks, Hall Crannell, M. M. Ito, S. Bültmann, W. J. Briscoe, E. Pasyuk, J. R. Johnstone, L. Guo, M. Ungaro, S. A. Dytman, M. Bellis, K. Joo, S. S. Stepanyan, A. Yegneswaran, V. Gyurjyan, J. Zhang, H. Bagdasaryan, J. W. Price, V. P. Kubarovsky, G. Rosner, O. Pogorelko, Frank Klein, Michael Wood, K. Hafidi, K. S. Egiyan, V. S. Serov, B. E. Stokes, G. S. Adams, K. Mikhailov, Clarisse Tur, P. Nadel-Turonski, Tsutomu Mibe, G. Gavalian, V. Mokeev, P. Stoler, W. Kim, J. Lachniet, K. Hicks, A. Tkabladze, R. S. Hakobyan, L. El Fassi, M. Osipenko, G. Asryan, O. P. Dzyubak, R. A. Niyazov, P. L. Cole, Z. W. Zhao, B. Zhao, F. W. Hersman, and R. W. Gothe
Subjects: Physics, Particle physics, Rho meson, Meson, Spectrometer, Nuclear Theory, Spectrum (functional analysis), General Physics and Astronomy, Order (ring theory), Physics and Astronomy(all), Resonance (particle physics), medicine.anatomical_structure, Deuterium, medicine, High Energy Physics::Experiment, Nuclear Experiment, Nucleus
Abstract: The photoproduction of vector mesons on various nuclei has been studied using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Laboratory. The vector mesons, $$\rho$$, $$\omega$$, and $$\phi$$, are observed via their decay to $e^+e^-$, in order to reduce the effects of final state interactions in the nucleus. Of particular interest are possible in-medium effects on the properties of the $$\rho$$ meson. The $$\rho$$ spectral function is extracted from the data on various nuclei, carbon, iron, and titanium, and compared to the spectrum from liquid deuterium, which is relatively free of nuclear effects. We observe no significant mass shift for the $$\rho$$ meson; however, there is some widening of the resonance in titanium and iron, which is consistent with expected collisional broadening.
Published: 2007
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23. Erratum: Cross sections for theγp→K*0Σ+reaction atEγ=1.7−3.0GeV [Phys. Rev. C75, 042201 (2007)]

Author: Shifeng Chen, L. C. Dennis, M. Osipenko, H. Avakian, K. Livingston, K. Beard, K. A. Griffioen, J. Donnelly, G. Asryan, M. Battaglieri, R. Bradford, B. A. Mecking, O. P. Dzyubak, R. A. Niyazov, H. Egiyan, J. T. Goetz, R. Dickson, D. Doughty, G. Rosner, Carlos A. Salgado, J. W C McNabb, D. Heddle, A.V. Stavinsky, A. V. Vlassov, Maryam Moteabbed, W. J. Briscoe, E. Pasyuk, K. S. Egiyan, E. S. Smith, D. G. Jenkins, W. Kim, Laird Kramer, D. J. Tedeschi, Kwangsoo Kim, J. Lachniet, A. Tkabladze, S. A. Dytman, S. E. Kuhn, B. B. Niczyporuk, G. Riccardi, K. Mikhailov, B. L. Berman, M. Amarian, N. Guler, R. De Vita, I. Bedlinskiy, Andreas Klein, J. Langheinrich, B. E. Stokes, V. Sapunenko, C. Butuceanu, Sylvain Bouchigny, N. Pivnyuk, E. Wolin, Stephen Taylor, K. Lukashin, Ji Li, U. Thoma, C. Paterson, M. Bellis, P. Rossi, Gerard Gilfoyle, S. McAleer, F. X. Girod, S. A. Morrow, G. Gavalian, P. Stoler, R. S. Hakobyan, V. Batourine, S. Niccolai, C. Djalali, J. P. Ball, D. G. Ireland, M. D. Mestayer, V. Crede, G. Ricco, Y. Prok, V. Mokeev, D. S. Carman, J. Hardie, M. MacCormick, B. Carnahan, F. Sabatié, K. Hicks, J. R. Calarco, P. Ambrozewicz, Michael L. Williams, I. Hleiqawi, S. L. Careccia, V. P. Kubarovsky, S. Strauch, Atilla Gonenc, H. Juengst, D. G. Crabb, J. P. Cummings, G. S. Mutchler, M. Guidal, Z. Krahn, L. C. Smith, E. Munevar, N. A. Baltzell, E. De Sanctis, O. Pogorelko, K. L. Giovanetti, G. Niculescu, R. W. Gothe, N. Baillie, R. A. Miskimen, B. McKinnon, M. Anghinolfi, Larry Weinstein, B. S. Ishkhanov, S. Boiarinov, D. I. Sober, D. Branford, L. Elouadrhiri, M. R. Niroula, Yordanka Ilieva, M. Mirazita, J. M. Laget, M. Kossov, Frank Klein, I. I. Strakovsky, J. D. Kellie, A. Deur, R. G. Fersch, Rakhsha Nasseripour, M. Holtrop, Michael Dugger, B. Zhao, M. Khandaker, Brian Raue, P. Coltharp, Y. G. Sharabian, M. M. Ito, A. I. Ostrovidov, Michael Wood, K. Park, Michael Vineyard, Hong Lu, P. L. Cole, Z. W. Zhao, F. W. Hersman, S. Whisnant, B. M. Preedom, V. S. Serov, Federico Ronchetti, Lorenzo Zana, Volker D. Burkert, A. S. Biselli, Clarisse Tur, P. Nadel-Turonski, H. S. Jo, Tsutomu Mibe, Gerald Feldman, C. E. Hyde-Wright, R. C. Minehart, K. Wang, C. A. Meyer, K. Moriya, R. J. Feuerbach, Jens H. Kuhn, Sergey Kuleshov, S. Tkachenko, N. Benmouna, V. Gyurjyan, M. Ripani, G. V. Fedotov, N. Kalantarians, L. Todor, J. Zhang, H. Bagdasaryan, D. Protopopescu, J. W. Price, L. Guo, S. Pozdniakov, M. Garçon, M. Ungaro, K. Joo, S. S. Stepanyan, A. Yegneswaran, D. P. Weygand, Alexei V. Klimenko, Barry Ritchie, G. E. Dodge, P. V. Degtyarenko, I. Niculescu, D. Lawrence, R. De Masi, R. A. Schumacher, M. Nozar, S. Bültmann, S. Stepanyan, J. Pierce, William Brooks, Hall Crannell, P. Eugenio, M. Taiuti, P. Collins, J. P. Santoro, and Roy Thompson
Subjects: Baryon, Nuclear reaction, Physics, Nuclear and High Energy Physics, Particle physics, Meson, Hadron, Elementary particle, Fermion, Boson, Sigma baryon
Published: 2007
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24. Determination of the pion charge form factor forQ2=0.60–1.60 GeV2

Author: D. van Westrum, Ketevi Assamagan, R. van der Meer, J. Reinhold, V. Tadevosyan, C. S. Armstrong, P. H. Kim, W. Zhao, I. Niculescu, K. Vansyoc, D. Gaskell, W. Hinton, H. E. Jackson, B. Zihlmann, Andreas Klein, J. A. Dunne, D. McKee, Ronald Gilman, C. Yan, W. F. Vulcan, Rolf Ent, H. Mkrtchyan, D. Abbott, D. G. Meekins, J. Arrington, M. K. Jones, W. Kim, G. J. Lolos, H. Anklin, Oliver Keith Baker, John C. Mitchell, T. Eden, S. Stepanyan, A. F. Lung, C. Bochna, D. H. Potterveld, L. M. Qin, K. Gustafsson, G. Niculescu, I. K. Shin, C. E. Keppel, H. Breuer, S. A. Wood, D. J. Mack, Stephen Avery, N. S. Chant, B. Mueller, M. Liang, E. J. Brash, J. Volmer, G. M. Huber, D. Koltenuk, D. Pitz, H. P. Blok, and L. G. Tang
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Cross section.transverse, Pion, 010308 nuclear & particles physics, Hydrogen-1, 0103 physical sciences, Form factor (quantum field theory), Charge (physics), 010306 general physics, 01 natural sciences
Abstract: The data analysis for the reaction {sup 1}H(e,e{sup '}{pi}{sup +})n, which was used to determine values for the charged pion form factor F{sub {pi}} for values of Q{sup 2}= 0.6-1.6 GeV{sup 2}, has been repeated with careful inspection of all steps and special attention to systematic uncertainties. Also the method used to extract F{sub {pi}} from the measured longitudinal cross section was critically reconsidered. Final values for the separated longitudinal and transverse cross sections and the extracted values of F{sub {pi}} are presented.
Published: 2007
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25. ProtonGE/GMfrom beam-target asymmetry

Author: J. P. Chen, C. Yan, Dinko Pocanic, R. A. Lindgren, L. Cole, C. Carasco, S. A. Wood, S. Danagoulian, L. G. Tang, M. Elaasar, D. Gaskell, F. R. Wesselmann, I. Niculescu, Rolf Ent, Geoffrey Smith, R. Asaturyan, S. Tajima, M. Zeier, L. H. Kramer, W.U. Boeglin, B. S. Hu, D. J. Mack, H. C. Fenker, M. Khandaker, Rakhsha Nasseripour, L. Yuan, O. Rondon, M. L. Seely, J. Lichtenstadt, H. Mkrtchyan, D. McNulty, C. E. Keppel, A. Ahmidouch, Y. Liang, J. Gomez, J. Jourdan, Emil Frlez, M. K. Jones, S. Stepanyan, Daniela Rohe, Andreas Klein, N. Savvinov, K. Wang, C. D. Keith, G. Testa, H. Zhu, Curtis Smith, W. F. Vulcan, J. Yun, Ingo Sick, Donal Day, B. Sawatzky, M. E. Christy, Karl Slifer, P. E. Bosted, J. Cha, J. Reinhold, Brian Raue, R. D. Carlini, L. Coman, B. E. Norum, J. A. Dunne, D. G. Meekins, Glen A. Warren, A. Aghalaryan, L. Gan, J. Roche, K. Normand, F. Bloch, Y. Prok, D. G. Crabb, and P. McKee
Subjects: Physics, Systematic error, Nuclear and High Energy Physics, Recoil, Proton, Scattering, media_common.quotation_subject, Magnetic form factor, Polarization observables, Atomic physics, Polarization (waves), Asymmetry, media_common
Abstract: The ratio of the proton's electric to magnetic form factor, G{sub E}/G{sub M}, can be extracted in elastic electron-proton scattering by measuring cross sections, beam-target asymmetry, or recoil polarization. Separate determinations of G{sub E}/G{sub M} by cross sections and recoil polarization observables disagree for Q{sup 2}>1 (GeV/c){sup 2}. Measurement by a third technique might uncover an unknown systematic error in either of the previous measurements. The beam-target asymmetry has been measured for elastic electron-proton scattering at Q{sup 2} = 1.51 (GeV/c){sup 2} for target spin orientation aligned perpendicular to the beam momentum direction. This is the largest Q{sup 2} at which G{sub E}/G{sub M} has been determined by a beam-target asymmetry experiment. The result, {mu}G{sub E}/G{sub M}=0.884{+-}0.027{+-}0.029, is compared to previous world data.
Published: 2006
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26. Polarization transfer in theH2(e→,e′p→)nreaction up toQ2=1.61(GeV/c)2

Author: G. J. Kumbartzki, John C. Mitchell, J. J. LeRose, K. Wijesooriya, M. K. Jones, S. Dumalski, V. Gorbenko, D. Rowntree, C. E. Keppel, R. Michaels, X. Jiang, Andreas Klein, J. Hovebo, Oliver Keith Baker, M. Kuss, C. Glashausser, J. R. Calarco, L. Todor, J. A. Gomez, E. J. Brash, Larry Weinstein, William Bertozzi, F. Garibaldi, Nilanga Liyanage, Ronald Gilman, Pete Markowitz, G. J. Lolos, R. J. Woo, C. F. Perdrisat, J.-O. Hansen, Z. Papandreou, Bogdan Wojtsekhowski, R. Roche, M. Liang, Hartmuth Arenhövel, P. E. Ulmer, Rolf Ent, A. Kozlov, J. P. Chen, S. Strauch, G. M. Urciuoli, A. Cochran, S. Kuhn, Shalev Gilad, E. Chudakov, John M. Finn, C. W. de Jager, A. Saha, B. Hu, V. A. Punjabi, D. G. Meekins, and S. Jeschonnek
Subjects: Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Electric form factor, Analytical chemistry, Electron, Polarization (waves), 7. Clean energy, 01 natural sciences, Nuclear physics, Recoil proton, 0103 physical sciences, Neutron, 010306 general physics
Abstract: The recoil proton polarization was measured in the {sup 2}H(e-vector,e{sup '}p-vector)n reaction in Hall A of the Thomas Jefferson National Accelerator Facility. The electron kinematics were centered on the quasielastic peak (x{sub Bj}{approx_equal}1) and included three values of the squared four-momentum transfer, Q{sup 2}=0.43,1.00 and 1.61 (GeV/c){sup 2}. For Q{sup 2}=0.43 and 1.61 (GeV/c){sup 2}, the missing momentum, p{sub m}, was centered at zero, whereas for Q{sup 2}=1.00 (GeV/c){sup 2} two values of p{sub m} were chosen: 0 and 174 MeV/c. At low p{sub m}, the Q{sup 2} dependence of the longitudinal polarization, P{sub z}{sup '}, is not well described by a state-of-the-art calculation. Further, at higher p{sub m}, a 3.5{sigma} discrepancy was observed in the transverse polarization, P{sub x}{sup '}. Understanding the origin of these discrepancies is important to confidently extract the neutron electric form factor from the analogous {sup 2}H(e-vector,e{sup '}n-vector)p experiment.
Published: 2006
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27. Surface states, surface potentials, and segregation at surfaces of tin-dopedIn2O3

Author: Spiros Zafeiratos, Andreas Klein, Yvonne Gassenbauer, Axel Knop-Gericke, Robert Schafranek, Robert Schlögl, and Michael Hävecker
Subjects: Materials science, Fermi level, Binding energy, Doping, chemistry.chemical_element, Sputter deposition, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, symbols.namesake, chemistry, X-ray photoelectron spectroscopy, symbols, Thin film, Atomic physics, Tin, Surface states
Abstract: Surfaces of In2O3 and tin-doped In2O3 (ITO) were investigated using photoelectron spectroscopy. Parts of the measurements were carried out directly after thin film preparation by magnetron sputtering without breaking vacuum. In addition samples were measured during exposure to oxidizing and reducing gases at pressures of up to 100 Pa using synchrotron radiation from the BESSY II storage ring. Reproducible changes of binding energies with temperature and atmosphere are observed, which are attributed to changes of the surface Fermi level position. We present evidence that the Fermi edge emission observed at ITO surfaces is due to metallic surface states rather than to filled conduction band states. The observed variation of the Fermi level position at the ITO surface with experimental conditions is accompanied by a large apparent variation of the core level to valence band maximum binding energy difference as a result of core-hole screening by the free carriers in the surface states. In addition segregation of Sn to the surface is driven by the surface potential gradient. At elevated temperatures the surface Sn concentration reproducibly changes with exposure to different environments and shows a correlation with the Fermi level position.
Published: 2006
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28. First-principles study of intrinsic point defects in ZnO: Role of band structure, volume relaxation, and finite-size effects

Author: Andreas Klein, Paul Erhart, and Karsten Albe
Subjects: Materials science, Condensed matter physics, Band gap, Relaxation (NMR), Condensed Matter Physics, Crystallographic defect, Semimetal, Electronic, Optical and Magnetic Materials, Condensed Matter::Materials Science, Physics::Atomic and Molecular Clusters, Direct and indirect band gaps, Physics::Chemical Physics, Electronic band structure, Scaling, Quasi Fermi level
Abstract: Density-functional theory (DFT) calculations of intrinsic point defect properties in zinc oxide were performed in order to remedy the influence of finite-size effects and the improper description of the band structure. The generalized gradient approximation (GGA) with empirical self-interaction corrections $(\mathrm{GGA}+U)$ was applied to correct for the overestimation of covalency intrinsic to GGA-DFT calculations. Elastic as well as electrostatic image interactions were accounted for by application of extensive finite-size scaling and compensating charge corrections. Size-corrected formation enthalpies and volumes as well as their charge state dependence have been deduced. Our results partly confirm earlier calculations but reveal a larger number of transition levels: (1) For both the zinc interstitial as well as the oxygen vacancy, transition levels are close to the conduction band minimum. (2) The zinc vacancy shows a transition rather close to the valence band maximum and another one near the middle of the calculated band gap. (3) For the oxygen interstitials, transition levels occur both near the valence band maximum and the conduction band minimum.
Published: 2006
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29. Erratum:η′Photoproduction on the Proton for Photon Energies from 1.527 to 2.227 GeV [Phys. Rev. Lett.96, 062001 (2006)]

Author: Laird Kramer, Dinko Pocanic, G. S. Mutchler, S. E. Kuhn, G. Rosner, Stephen Taylor, Yordanka Ilieva, M. D. Mestayer, J. J. Manak, P. Eugenio, M. Osipenko, Shifeng Chen, M. Taiuti, S. Boiarinov, B. M. Preedom, M. Guidal, G. Niculescu, K. Beard, K. Livingston, K. S. Egiyan, M. Holtrop, R. A. Schumacher, Lorenzo Zana, Frank Klein, K. Mikhailov, M. Guillo, J. T. Goetz, J. Langheinrich, S. A. Philips, K. A. Griffioen, V. Batourine, D. G. Ireland, V. Crede, S. A. Morrow, P. Rubin, L. Elouadrhiri, A.V. Stavinsky, H. S. Jo, Gerald Feldman, J. R. Calarco, N. Guler, G. Gavalian, C. Djalali, G. Audit, C. E. Hyde-Wright, R. J. Feuerbach, M. Bektasoglu, J. Shaw, N. A. Baltzell, I. I. Strakovsky, B. Carnahan, F. Sabatié, K. Wang, B. E. Stokes, G. S. Adams, D. J. Tedeschi, V. Mokeev, J. P. Cummings, J. Hu, E. Wolin, P. Ambrozewicz, Michael Wood, A. Deur, J. Donnelly, G. Asryan, S. Barrow, O. P. Dzyubak, R. A. Niyazov, H. Juengst, V. S. Serov, R. A. Miskimen, B. McKinnon, I. Bedlinskiy, M. Anghinolfi, G. V. O'Rielly, J. P. Ball, Y. Prok, M. Kossov, Andreas Klein, K. V. Dharmawardane, M. Nozar, P. Corvisiero, James Mueller, Rakhsha Nasseripour, K. S. Dhuga, D. Branford, J. P. Santoro, M. Bellis, E. S. Smith, Marco A. Huertas, D. S. Carman, A. Coleman, H. R. Weller, Roy Thompson, D. Protopopescu, T. A. Forest, D. G. Jenkins, J. D. Kellie, Y. G. Sharabian, Cynthia Marie Hadjidakis, E. De Sanctis, M. Mirazita, J. M. Laget, M. Battaglieri, P. Collins, M. Spraker, V. Gyurjyan, A. I. Ostrovidov, P. Stoler, A. C S Lima, K. Park, L. C. Smith, S. Pozdniakov, M. Garçon, B. S. Ishkhanov, P. L. Cole, Michael Vineyard, A. Shafi, Mark Richard James Williams, S. Stepanyan, Sylvain Bouchigny, R. Bradford, B. A. Mecking, P. Rossi, R. DeVita, J. Zhang, V. P. Kubarovsky, D. G. Crabb, Michael Dugger, Volker D. Burkert, H. Egiyan, J. Pierce, J. W C McNabb, K. Hicks, W. Kim, Clarisse Tur, P. Nadel-Turonski, H. Bagdasaryan, J. W. Price, V. Sapunenko, Valeria Muccifora, A. Empl, O. Pogorelko, A. S. Biselli, P. Dragovitsch, D. I. Sober, S. McAleer, F. X. Girod, Tsutomu Mibe, B. L. Berman, H. O. Funsten, S. Niccolai, L. M. Qin, Gerard Gilfoyle, B. B. Niczyporuk, William Brooks, U. Thoma, L. C. Dennis, B. E. Bonner, P. Coltharp, N. Pivnyuk, K. Lukashin, J. Napolitano, Hall Crannell, H. Avakian, M. M. Ito, J. Hardie, S. Strauch, Jens H. Kuhn, C. Paterson, Nicola Bianchi, L. C. Maximon, C. Marchand, M. Klusman, J. Lachniet, A. Tkabladze, L. Guo, M. Ungaro, G. E. Dodge, D. Rowntree, P. V. Degtyarenko, K. Kim, S. Bültmann, W. J. Briscoe, E. Pasyuk, K. Joo, J. Yun, D. Cords, S. S. Stepanyan, N. Baillie, S. A. Dytman, R. S. Hakobyan, R. Fatemi, A. Yegneswaran, D. Lawrence, A. V. Vlassov, Kwangsoo Kim, G. Riccardi, C. Butuceanu, S. Tkachenko, N. Benmouna, T. Lee, M. Ripani, Carlos A. Salgado, G. Ricco, Brian Raue, Federico Ronchetti, R. C. Minehart, C. A. Meyer, G. V. Fedotov, D. P. Weygand, D. Doughty, H. Denizli, D. Heddle, A. V. Skabelin, Alexei V. Klimenko, Barry Ritchie, E. Anciant, M. Khandaker, I. Hleiqawi, S. L. Careccia, S. Simionatto, K. L. Giovanetti, B. Asavapibhop, Larry Weinstein, F. W. Hersman, and R. W. Gothe
Subjects: Physics, Nuclear physics, Meson production, Photon, Proton, General Physics and Astronomy
Published: 2006
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30. Erratum: Radiative decays of theΣ0(1385)andΛ(1520)hyperons [Phys. Rev. C71, 054609 (2005)]

Author: A. V. Vlassov, T. Lee, M. Spraker, Michael Vineyard, G. V. O'Rielly, B. E. Stokes, G. S. Adams, D. G. Jenkins, B. S. Raue, J. P. Santoro, R. DeVita, J. W C McNabb, L. Todor, Roy Thompson, Kwangsoo Kim, G. Riccardi, C. Butuceanu, D. Protopopescu, S. Pozdniakov, M. Garçon, E. Wolin, J. P. Ball, Y. Prok, D. S. Carman, D. G. Crabb, Yordanka Ilieva, Ji Li, W. Kim, J. P. Cummings, R. A. Schumacher, L. Elouadrhiri, M. Kossov, Rakhsha Nasseripour, K. S. Egiyan, I. I. Strakovsky, V. Koubarovski, C. I O Gordon, M. Bellis, K. Mikhailov, M. M. Ito, M. Nozar, A. Deur, E. De Sanctis, L. Morand, T. A. Forest, S. Stepanyan, Federico Ronchetti, D. I. Sober, A. Empl, O. Pogorelko, L. C. Dennis, B. E. Bonner, G. Ricco, G. S. Mutchler, H. Avakian, V. Batourine, C. A. Meyer, E. Golovatch, G. Asryan, S. Bültmann, B. Carnahan, O. P. Dzyubak, R. A. Niyazov, W. J. Briscoe, E. Pasyuk, F. Sabatié, J. D. Kellie, S. A. Dytman, M. D. Mestayer, J. J. Manak, P. Corvisiero, M. Anghinolfi, U. Thoma, H. R. Weller, G. E. Dodge, Frank Klein, James Mueller, P. V. Degtyarenko, K. Kim, K. V. Dharmawardane, L. C. Smith, J. Shaw, D. P. Weygand, Michael Wood, Y. G. Sharabian, S. A. Morrow, P. Stoler, I. Niculescu, A. Shafi, P. Rubin, C. Djalali, S. Boiarinov, D. Lawrence, M. Guillo, J. Langheinrich, K. Hicks, V. S. Serov, M. Osipenko, S. A. Philips, Shifeng Chen, William Brooks, G. Rosner, Hall Crannell, H. Denizli, V. Sapunenko, C. Marchand, Valeria Muccifora, B. L. Berman, M. Battaglieri, L. M. Qin, P. Ambrozewicz, F. W. Hersman, H. Juengst, A. I. Ostrovidov, A. C S Lima, K. Park, Gerard Gilfoyle, E. Polli, M. Klusman, R. W. Gothe, G. Audit, C. E. Hyde-Wright, A. V. Skabelin, R. J. Feuerbach, Dinko Pocanic, M. Bektasoglu, Alexei V. Klimenko, R. Bradford, B. A. Mecking, Volker D. Burkert, A. S. Biselli, S. E. Kuhn, Cynthia Marie Hadjidakis, B. M. Preedom, M. Guidal, Barry Ritchie, G. Niculescu, P. Eugenio, Stephen Taylor, S. McAleer, M. Taiuti, K. A. Griffioen, Michael Dugger, M. Holtrop, H. O. Funsten, B. B. Niczyporuk, S. Strauch, J. J. Melone, Laird Kramer, D. G. Ireland, N. Pivnyuk, Lorenzo Zana, J. R. Calarco, K. Lukashin, J. Napolitano, R. A. Miskimen, Carlos A. Salgado, D. Branford, J. Hu, Gerald Feldman, M. Mirazita, J. M. Laget, K. Wang, N. Benmouna, M. Ripani, E. S. Smith, Marco A. Huertas, Sylvain Bouchigny, P. Rossi, Mark Richard James Williams, P. Dragovitsch, S. Niccolai, J. Hardie, A.V. Stavinsky, D. J. Tedeschi, K. Beard, Andreas Klein, G. Gavalian, V. Mokeev, D. Doughty, D. Heddle, J. Lachniet, A. Tkabladze, H. Egiyan, E. Anciant, C. S. Whisnant, D. Rowntree, M. Khandaker, V. Gyurjyan, K. Livingston, R. S. Hakobyan, N. Guler, H. Bagdasaryan, J. W. Price, L. Guo, S. Barrow, M. Ungaro, I. Hleiqawi, K. Joo, J. Yun, D. Cords, S. S. Stepanyan, A. Yegneswaran, R. G. Fersch, S. Simionatto, P. L. Cole, K. L. Giovanetti, B. Asavapibhop, Larry Weinstein, Clarisse Tur, Jens H. Kuhn, Nicola Bianchi, R. Suleiman, and R. Fatemi
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Hyperon, Radiative decay, Radiative transfer, Sigma, Lambda, Particle identification
Published: 2005
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31. First-principles study of the structure and stability of oxygen defects in zinc oxide

Author: Karsten Albe, Paul Erhart, and Andreas Klein
Subjects: Materials science, Condensed matter physics, business.industry, chemistry.chemical_element, Zinc, Crystal structure, Condensed Matter Physics, Crystallographic defect, Oxygen, Electronic, Optical and Magnetic Materials, Condensed Matter::Materials Science, Semiconductor, chemistry, Chemical bond, Chemical physics, Covalent bond, Density functional theory, Physics::Chemical Physics, business
Abstract: A comparative study on the structure and stability of oxygen defects in ZnO is presented. By means of first-principles calculations based on local density functional theory we investigate the oxygen vacancy and different interstitial configurations of oxygen in various charge states. Our results reveal that dumbbell-like structures are thermodynamically the most stable interstitial configurations for neutral and positive charge states due to the formation of a strongly covalent oxygen--oxygen bond. For negative charge states the system prefers a split-interstitial configuration with two oxygen atoms in almost symmetric positions with respect to the associated perfect lattice site. The calculated defect formation energies imply that interstitial oxygen atoms may provide both donor- and acceptor-like defects.
Published: 2005
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32. Near threshold electroproduction of theωmeson atQ2≈0.5GeV2

Author: L. Ewell, J. Arrington, D. Abbott, S. Danagoulian, J. A. Dunne, John C. Mitchell, D. G. Meekins, Brian Raue, T. Eden, J.-O. Hansen, J. Reinhold, H. Mkrtchyan, H. T. Fortune, Dipanwita Dutta, L. G. Tang, V. Tadevosyan, Oliver Keith Baker, R. Sawafta, G. Niculescu, C. Cothran, Richard Madey, B. Zihlmann, D. H. Potterveld, Kevin Bailey, B. Zeidman, Ketevi Assamagan, R. D. Carlini, Andreas Klein, Donal Day, B. Terburg, J. W. Price, Pete Markowitz, J. Cha, C. Yan, C. S. Armstrong, W. J. Cummings, D. Koltenuk, A. Ahmidouch, K. Gustafsson, F. Duncan, G. Collins, Thomas O'Neill, I. Niculescu, Rolf Ent, G. Savage, Haiyan Gao, W. Hinton, Paul Gueye, D. F. Geesaman, S. A. Wood, S. Stepanyan, P. G. Roos, H. Breuer, D. J. Mack, C. E. Keppel, R. E. Segel, R. Mohring, S. Beedoe, S. Mtingwa, P. Ambrozewicz, and C. J. Martoff
Subjects: Physics, Nuclear and High Energy Physics, Angular range, Particle physics, Photon, Meson production, Meson, 010308 nuclear & particles physics, Parity (physics), 01 natural sciences, Omega, Nuclear physics, Near threshold, Angular distribution, 0103 physical sciences, Nuclear Experiment, 010306 general physics
Abstract: Electroproduction of the {omega} meson was investigated in the {sup 1}H(e,e{sup '}p){omega} reaction. The measurement was performed at a four-momentum transfer Q{sup 2}{approx_equal}0.5 GeV{sup 2}. Angular distributions of the virtual photon-proton center-of-momentum cross sections have been extracted over the full angular range. These distributions exhibit a strong enhancement over t-channel parity exchange processes in the backward direction. According to a newly developed electroproduction model, this enhancement provides significant evidence of resonance formation in the {gamma}*p{yields}{omega}p reaction channel.
Published: 2004
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33. Publisher’s Note: Two-Nucleon Momentum Distributions Measured inHe3(e,e′pp)n[Phys. Rev. Lett.PRLTAO0031-900792, 052303 (2004)]

Author: K. A. Griffioen, Shifeng Chen, G. Gavalian, S. McAleer, Y. Kuang, J. Langheinrich, Cynthia Marie Hadjidakis, S. A. Philips, E. Wolin, E. Polli, Michael Dugger, R. DeVita, H. O. Funsten, J. W C McNabb, S. Strauch, J. P. Ball, Y. Prok, P. L. Cole, D. S. Carman, Dinko Pocanic, V. Gyurjyan, H. Bagdasaryan, J. W. Price, Min Suk Kim, J. R. Calarco, R. A. Schumacher, Frank Klein, S. E. Kuhn, J. P. Cummings, J. Hu, C. A. Meyer, G. S. Mutchler, J. H. Kelley, Stephen Taylor, R. Fatemi, Carlos A. Salgado, C. I O Gordon, Patrick Girard, J. Shaw, Federico Ronchetti, G. Audit, C. E. Hyde-Wright, S. A. Morrow, P. Rubin, M. Eckhause, C. Djalali, A. V. Vlassov, D. G. Crabb, L. Ciciani, M. Nozar, Michael Wood, G. V. O'Rielly, R. J. Feuerbach, J. Lachniet, L. Morand, D. Rowntree, M. Kossov, T. A. Forest, V. S. Serov, G. Ricco, S. Stepanyan, P. Ambrozewicz, H. Juengst, M. Osipenko, J. R. Ficenec, M. Bektasoglu, Rakhsha Nasseripour, N. Dashyan, D. G. Jenkins, M. Bellis, K. Sabourov, M. Anghinolfi, K. Park, Shalev Gilad, S. Simionatto, E. S. Smith, James Mueller, K. Beard, R. S. Hakobyan, E. De Sanctis, P. Eugenio, L. C. Smith, B. Carnahan, G. E. Dodge, F. Sabatié, D. P. Weygand, M. Guidal, Y. G. Sharabian, Sylvain Bouchigny, Yordanka Ilieva, D. I. Sober, P. Dragovitsch, Ji Li, Brian Raue, P. Rossi, G. Niculescu, Daijin Kim, P. V. Degtyarenko, K. Kim, Volker D. Burkert, A. S. Biselli, B. B. Niczyporuk, W. Kim, M. Taiuti, N. Pivnyuk, K. L. Giovanetti, B. Asavapibhop, S. Niccolai, A. Empl, O. Pogorelko, M. Holtrop, M. D. Mestayer, J. J. Manak, Clarisse Tur, K. Lukashin, J. Napolitano, L. C. Dennis, I. Niculescu, D. Lawrence, Laird Kramer, Alexei V. Klimenko, Larry Weinstein, B. E. Bonner, Thierry Auger, J. Hardie, H. Avakian, G. Asryan, O. P. Dzyubak, R. A. Niyazov, N. Benmouna, M. Ripani, D. Doughty, K. V. Dharmawardane, S. Boiarinov, S. Mehrabyan, Barry Ritchie, D. Heddle, Kwangsoo Kim, G. Riccardi, William Brooks, Hall Crannell, C. Butuceanu, P. Corvisiero, M. Spraker, C. Cetina, Michael Vineyard, J. D. Kellie, K. S. Dhuga, C. Marchand, B. M. Preedom, J. J. Melone, William Bertozzi, E. Anciant, B. L. Berman, L. M. Qin, E. Pasyuk, M. Khandaker, K. Wang, J. P. Santoro, M. Klusman, S. A. Dytman, Roy Thompson, M. Battaglieri, P. Stoler, A. Coleman, S. O. Nelson, H. Denizli, H. R. Weller, K. Hicks, K. S. Egiyan, R. Bradford, B. A. Mecking, K. Mikhailov, A. V. Skabelin, M. M. Ito, H. Egiyan, S. McLauchlan, C. S. Whisnant, G. S. Adams, L. Todor, D. Protopopescu, S. Pozdniakov, A. Shafi, U. Thoma, Jens H. Kuhn, Nicola Bianchi, K. Livingston, W. Ingram, F. W. Hersman, G. A. Peterson, M. Guillo, S. Barrow, R. W. Gothe, L. Elouadrhiri, R. A. Miskimen, I. I. Strakovsky, L. Guo, M. Ungaro, K. Joo, D. Branford, J. Yun, D. Cords, A. Yegneswaran, M. Mirazita, J. M. Laget, V. Sapunenko, Valeria Muccifora, A.V. Stavinsky, D. J. Tedeschi, Gerard Gilfoyle, Andreas Klein, and Baile Zhang
Subjects: Physics, Momentum (technical analysis), General Physics and Astronomy, Few-body systems, Nucleon, Mathematical physics
Published: 2004
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34. Measurement of the Electric Form Factor of the Neutron atQ2=0.5and1.0 GeV2/c2

Author: B. Norum, B. Vlahovic, L. Cole, R. Trojer, D. McNulty, S. A. Wood, I. Goussev, Hartmuth Arenhövel, L. Coman, S. E. Kuhn, James J. Kelly, B. Vulcan, C. Yan, Alexei V. Klimenko, Jonathan A.D. Farrell, S. Tajima, D. J. Mack, G. Testa, R. Asaturyan, N. S. Chant, M. L. Seely, Andreas Klein, K. Wang, J. Roche, A. K. Opper, Rakhsha Nasseripour, John C. Mitchell, Eli Piasetzky, Curtis Smith, J. Lichtenstadt, Ingo Sick, C. D. Keith, Pete Markowitz, Laird Kramer, R. Fatemi, B. Boillat, M. Khandaker, M. Hauger, D. Sacker, J. A. Dunne, N. Savvinov, M. Coman, M. Steinacher, H. Zhu, H. Breuer, F. Bloch, O. A. Rondon, Daniela Rohe, L. Yuan, J. Brower, Brian Raue, B. Hu, Y. Yanay, Paul Gueye, D. G. Meekins, I. Jaegle, K. Normand, Ashot Gasparian, B. Krusche, M. Harvey, C. E. Keppel, I. Ben-Dayan, E. Christy, T. A. Forest, H. Mkrtchyan, S. Stepanyan, M. Carl, J. Pierce, Y. Liang, H. Woehrle, J. Cha, J. Yun, R. Herrera, B. Sawatzky, L. G. Tang, J. Jourdan, H. C. Fenker, R. A. Lindgren, A. Ahmidouch, J. Stout, M. Pitt, G. Maclachlan, M. K. Jones, M. Zeier, M. Elaasar, I. Niculescu, Y. Prok, F. R. Wesselmann, A. F. Lung, D. G. Crabb, P. McKee, S. Wells, S. Danagoulian, Donal Day, J. Liu, George Davey Smith, J. Reinhold, W. U. Boeglin, Glen A. Warren, A. Aghalaryan, V. Tadevosyan, C. Carasco, B. Zihlmann, R. D. Carlini, D. Fawcett, Neven Simicevic, K. Garrow, K. Duek, and Rolf Ent
Subjects: Elastic scattering, Physics, Magnetization, Deuterium, Momentum transfer, Electric form factor, General Physics and Astronomy, High Energy Physics::Experiment, Neutron, Electron, Atomic physics, Nuclear Experiment, Nucleon
Abstract: The electric form factor of the neutron was determined from measurements of the (d) over right arrow((e) over right arrow ,e(`)n)p reaction for quasielastic kinematics. Polarized electrons were scattered off a polarized deuterated ammonia ((ND3)-N-15) target in which the deuteron polarization was perpendicular to the momentum transfer. The scattered electrons were detected in a magnetic spectrometer in coincidence with neutrons in a large solid angle detector. We find G(E)(n)=0.0526+/-0.0033(stat)+/-0.0026(sys) and 0.0454+/-0.0054+/-0.0037 at Q(2)=0.5 and 1.0 (GeV/c)(2), respectively.
Published: 2004
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35. Band symmetries of GaSe(0001) studied by spin-resolved electron spectroscopy using circularly polarized radiation

Author: Peter Blaha, C. Pettenkofer, Ulrich Heinzmann, Andreas Klein, Norbert Müller, and S.-W. Yu
Subjects: Physics, Valence (chemistry), Auger effect, Spin polarization, Synchrotron radiation, Condensed Matter Physics, Electron spectroscopy, Spectral line, Electronic, Optical and Magnetic Materials, symbols.namesake, Physics::Atomic and Molecular Clusters, symbols, Condensed Matter::Strongly Correlated Electrons, Atomic physics, Relativistic quantum chemistry, Excitation
Abstract: We have studied the symmetry properties of the bands of the layered semiconductor GaSe along the $\ensuremath{\Delta}$ direction by means of spin-resolved electron spectroscopy using circularly polarized synchrotron radiation and by means of a relativistic LAPW band-structure calculation. The photoelectron spectra show in the main a pair of weakly dispersing peaks caused by direct transitions from valence-band states with symmetries ${\ensuremath{\Delta}}_{9}^{5},$ ${\ensuremath{\Delta}}_{9}^{6}$ and ${\ensuremath{\Delta}}_{7}^{5},$ ${\ensuremath{\Delta}}_{8}^{6}.$ Our data determine the spin-orbit splitting of these valence bands to be $\ensuremath{\Delta}{E}_{\mathrm{so}}=0.3\ifmmode\pm\else\textpm\fi{}0.1\mathrm{eV}.$ We find a gap in the unoccupied bands along $\ensuremath{\Delta}$ about 8 eV above the fundamental gap. The analysis of the photoelectron spin polarization reveals that also unoccupied states with low symmetries ${\ensuremath{\Delta}}_{7}^{5},$ ${\ensuremath{\Delta}}_{8}^{6}$ and ${\ensuremath{\Delta}}_{9}^{5},$ ${\ensuremath{\Delta}}_{9}^{6}$ are involved in excitation and emission. Spin resolved spectra measured at Auger electrons following the decay of Ga 3d core holes confirm that p derived unoccupied states exists below the vacuum level.
Published: 2004
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36. Publisher’s Note:ηPhotoproduction on the Proton for Photon Energies from 0.75 to 1.95 GeV [Phys. Rev. Lett.89, 222002 (2002)]

Author: V. V. Frolov, D. Doughty, R. A. Niyazov, John T. O'Brien, D. Heddle, Barry Ritchie, S. A. Morrow, P. Rubin, M. Eckhause, C. Djalali, P. Dragovitsch, K. A. Griffioen, G. E. Dodge, M. Lucas, P. Corvisiero, D. Hancock, E. S. Smith, Sylvain Bouchigny, P. Rossi, P. V. Degtyarenko, S. Niccolai, Carlos A. Salgado, L. Elouadrhiri, G. Ricco, J. Hardie, K. S. Egiyan, Baile Zhang, R. C. Minehart, C. A. Meyer, G. S. Mutchler, V. Koubarovski, K. Mikhailov, G. Gavalian, A. K. Opper, I. Niculescu, M. M. Ito, I. I. Strakovsky, A.V. Stavinsky, D. Lawrence, M. Spraker, C. Cetina, H. Egiyan, G. V. O'Rielly, E. Wolin, Michael Vineyard, J. P. Cummings, D. P. Weygand, L. Farhi, Y. Kuang, D. J. Tedeschi, C. S. Whisnant, D. G. Jenkins, K. Sabourov, G. P. Capitani, E. Polli, William Brooks, G. S. Adams, R. DeVita, J. W C McNabb, Ji Li, H. Denizli, Hall Crannell, M. U. Mozer, P. Heimberg, M. Witkowski, K. V. Dharmawardane, A. Coleman, P. L. Cole, Cynthia Marie Hadjidakis, Andreas Klein, J. R. Ficenec, S. McAleer, J. D. Kellie, P. Stoler, J. Lachniet, H. R. Weller, M. Kossov, J. R. Calarco, C. Marchand, M. D. Mestayer, J. J. Manak, D. Rowntree, M. Anghinolfi, James Mueller, Michael Dugger, J. Connelly, A. V. Skabelin, K. S. Dhuga, D. Pogorelko, H. O. Funsten, S. O. Nelson, Y. G. Sharabian, Frank Klein, L. C. Smith, Rakhsha Nasseripour, S. J. Gaff, K. Hicks, M. Sanzone-Arenhovel, R. A. Schumacher, S. Boiarinov, B. B. Niczyporuk, B. M. Preedom, S. Strauch, S. A. Philips, W. Kim, N. Pivnyuk, C. I O Gordon, K. Lukashin, J. Napolitano, Moshe Gai, Dinko Pocanic, M. Battaglieri, Shalev Gilad, M. Nozar, S. E. Kuhn, L. Morand, T. A. Forest, B. Carnahan, F. Sabatié, K. L. Giovanetti, B. Asavapibhop, J. H. Kelley, Stephen Taylor, J. P. Ball, Y. Prok, Patrick Girard, R. Bradford, B. A. Mecking, Larry Weinstein, Gerald Feldman, J. Shaw, S. Stepanyan, D. S. Carman, Jens H. Kuhn, A. Longhi, E. Anciant, K. Wang, U. Thoma, Nicola Bianchi, Thierry Auger, Michael Wood, R. S. Hicks, Brian Raue, K. Livingston, V. S. Serov, L. C. Dennis, M. Khandaker, G. Audit, M. Ripani, M. Guillo, C. E. Hyde-Wright, B. L. Berman, L. M. Qin, H. Avakian, R. J. Feuerbach, K. Beard, M. Klusman, D. G. Crabb, G. A. Peterson, W. Major, M. Bektasoglu, S. Barrow, M. Guidal, G. Niculescu, W. J. Briscoe, E. Pasyuk, Federico Ronchetti, M. Holtrop, Thomas E. Smith, S. A. Dytman, L. Todor, J. S. McCarthy, M. Bellis, D. Protopopescu, L. Y. Murphy, S. Pozdniakov, S. Mehrabyan, Z. L. Zhou, R. Clark, A. Shafi, G. Riccardi, J. P. Santoro, Roy Thompson, Jing Zhao, M. Taiuti, V. Sapunenko, Valeria Muccifora, Gerard Gilfoyle, F. W. Hersman, R. A. Miskimen, D. Branford, M. Mirazita, J. M. Laget, Laird Kramer, R. Fatemi, A. V. Vlassov, K. Park, D. I. Sober, Volker D. Burkert, A. S. Biselli, L. Guo, M. Ungaro, K. Joo, J. Yun, D. Cords, A. Yegneswaran, E. DeSanctis, V. Gyurjyan, H. Bagdasaryan, and J. W. Price
Subjects: Physics, Nuclear physics, Photon, Proton, General Physics and Astronomy
Published: 2002
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37. Density-functional-theory calculations of electronic band structure of single-crystal and single-layerWS2

Author: Karsten Albe and Andreas Klein
Subjects: Nanostructure, Materials science, Basis (linear algebra), Band gap, Density functional theory, Heterojunction, Atomic physics, Electronic band structure, Single crystal, Single layer
Abstract: Electronic band structures of single-crystal and single-layer WS2 are investigated by first-principles calculations based on local-density-functional theory using a plane-wave basis with ultrasoft pseudopotentials. The band structure calculated for the single crystal corresponds very well with experimental data and recent calculations using an augmented-spherical wave basis [A. Klein et al., Phys. Rev. B 64, 205416 (2001)]. The calculations for the single layer show that compared to the bulk case no significant structural relaxations of the atomic positions occur. This result is confirmed by the good agreement of our calculated band structures for the single layer with the data from angle-resolved photoemission measurements.
Published: 2002
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38. Electronic band structure of single-crystal and single-layerWS2:Influence of interlayer van der Waals interactions

Author: Volker Eyert, Wolfram Jaegermann, S. Tiefenbacher, C. Pettenkofer, and Andreas Klein
Subjects: Materials science, Condensed matter physics, Band gap, Heterojunction, Electronic structure, Brillouin zone, Condensed Matter::Materials Science, symbols.namesake, Condensed Matter::Superconductivity, symbols, Density functional theory, van der Waals force, Electronic band structure, Single crystal
Abstract: The valence band structure of the layered transition metal dichalcogenide ${\mathrm{WS}}_{2}$ has been determined experimentally by angle resolved photoelectron spectroscopy and theoretically by augmented spherical wave band structure calculations as based on density functional theory. Good agreement between experimental and calculated band structure is observed for single crystal ${\mathrm{WS}}_{2}.$ An experimental band structure of a single layer was determined from an electronically decoupled film prepared on a single crystalline graphite substrate by metal-organic van der Waals epitaxy. The polarization dependent photoemission selection rules of the single layer film are appropriate for a free standing film. The experimental single layer band structure shows some differences compared to band structure calculations using bulk atomic positions within the layer. We conclude that relaxation of the single layer occurs as a consequence of the missing interlayer interactions leading to close agreement between electronic structure of the single layer and single crystal. As a consequence of the missing interlayer interactions the valence band maximum for the single layer is located at the K point of the Brillouin zone.
Published: 2001
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39. Corrected Article: Exclusive electroproduction of φ mesons at 4.2 GeV [Phys. Rev. C63, 065205 (2001)]

Author: J. Domingo, R. A. Schumacher, R. A. Niyazov, John T. O'Brien, G. S. Mutchler, H. O. Funsten, Dinko Pocanic, E. S. Smith, A. Coleman, H. R. Weller, M. D. Mestayer, J. J. Manak, S. E. Kuhn, P. Corvisiero, S. McAleer, J. H. Kelley, Stephen Taylor, Sylvain Bouchigny, P. Rossi, T. A. Forest, S. Stepanyan, K. S. Dhuga, G. Gavalian, S. Boiarinov, J. R. Ficenec, M. Anghinolfi, K. A. Griffioen, J. R. Calarco, S. A. Philips, L. C. Dennis, B. E. Bonner, H. Avakian, K. S. Egiyan, M. M. Ito, Laird Kramer, B. B. Niczyporuk, Jing Zhao, James Mueller, L. C. Smith, S. J. Gaff, K. Mikhailov, Shalev Gilad, G. E. Dodge, J. S. McCarthy, M. Taiuti, R. Fatemi, Y. G. Sharabian, J. Hu, M. Ripani, N. Pivnyuk, K. Lukashin, J. Napolitano, E. Wolin, Michael Vineyard, P. Dragovitsch, G. V. O'Rielly, Baile Zhang, M. Guidal, A. K. Opper, W. J. Briscoe, E. Pasyuk, M. Battaglieri, A. V. Vlassov, D. G. Jenkins, K. Park, B. A. Mecking, J. P. Ball, D. S. Carman, P. Rubin, M. Eckhause, H. Egiyan, C. Djalali, S. Whisnant, B. M. Preedom, K. Sabourov, G. Niculescu, J. P. Cummings, L. M. Qin, S. A. Dytman, R. A. Miskimen, Volker D. Burkert, A. S. Biselli, D. G. Crabb, J. Hardie, V. Gyurjyan, E. Polli, P. Stoler, Kevin Fissum, M. Holtrop, A.V. Stavinsky, D. Branford, M. Guillo, M. Kossov, M. Mirazita, S. O. Nelson, K. Wang, W. Kim, J. M. Laget, S. Pozdniakov, L. Elouadrhiri, D. J. Tedeschi, K. Hicks, C. Salgado, Robert E. Welsh, Roy Thompson, K. Paschke, I. I. Strakovsky, Z. L. Zhou, M. Klusman, Andreas Klein, V. Sapunenko, Valeria Muccifora, J. W. Price, Kwangsoo Kim, G. Riccardi, A. Longhi, G. S. Adams, R. Clark, Gerard Gilfoyle, R. DeVita, J. W C McNabb, A. Empl, Pavel Degtiarenko, E. De Sanctis, G. Audit, O. Pogorelko, C. E. Hyde-Wright, D. I. Sober, R. J. Feuerbach, K. Beard, Frank Klein, G. A. Peterson, S. Barrow, M. Bektasoglu, K. Joo, Patrick Girard, J. Shaw, J. Yun, D. Cords, A. Yegneswaran, Nicola Bianchi, B. Carnahan, F. Sabatié, V. S. Serov, Thierry Auger, A. R. Reolon, A. P. Freyberger, Federico Ronchetti, G. Ricco, Moshe Gai, R. S. Hicks, Brian Raue, Barry Ritchie, R. C. Minehart, C. A. Meyer, L. Ciciani, S. Simionatto, K. L. Giovanetti, B. Asavapibhop, Larry Weinstein, William Bertozzi, E. Anciant, M. Khandaker, D. P. Weygand, D. Doughty, D. Heddle, A. V. Skabelin, K. Kim, I. Niculescu, D. Lawrence, William Brooks, Hall Crannell, C. Marchand, D. Rowntree, L. Yanik, P. L. Cole, and F. W. Hersman
Subjects: Physics, Elastic scattering, Nuclear and High Energy Physics, Particle physics, Meson production, Proton, Meson, Vector meson dominance, Production (computer science), HERA
Abstract: We studied the exclusive reaction $e\stackrel{\ensuremath{\rightarrow}}{p}{e}^{\ensuremath{'}}{p}^{\ensuremath{'}}\ensuremath{\varphi}$ using the $\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\varphi}}{K}^{+}{K}^{\ensuremath{-}}$ decay mode. The data were collected using a 4.2 GeV incident electron beam and the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. Our experiment covers the range in ${Q}^{2}$ from 0.7 to 2.2 ${\mathrm{GeV}}^{2},$ and W from 2.0 to 2.6 GeV. Taken together with all previous data, we find a consistent picture of $\ensuremath{\varphi}$ production on the proton. Our measurement shows the expected decrease of the t slope with the vector-meson formation time $c\ensuremath{\Delta}\ensuremath{\tau}$ below 2 fm. At $〈c\ensuremath{\Delta}\ensuremath{\tau}〉=0.6$ fm, we measure ${b}_{\ensuremath{\varphi}}=2.27\ifmmode\pm\else\textpm\fi{}0.42$ ${\mathrm{GeV}}^{\ensuremath{-}2}.$ The cross section dependence on W as ${W}^{0.2\ifmmode\pm\else\textpm\fi{}0.1}$ at ${Q}^{2}=1.3$ ${\mathrm{GeV}}^{2}$ was determined by comparison with $\ensuremath{\varphi}$ production at HERA after correcting for threshold effects. This is the same dependence as observed in photoproduction.
Published: 2001
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