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42 results on '"NIE, YANGUANG"'

4. Photoelectronic scoping of adatoms, atomic vacancies, and the outermost layer of a surface

Author

Wang, Yan, Nie, Yanguang, Pan, Jisheng, Qin, Wei, Zhou, Zhaofeng, Zheng, Weitao, and Sun, Chang Q.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

An effective yet simple means disclosed herewith has allowed us to gain the atomistic, local, and quantitative information of bonds and electrons at sites surrounding undercoordinated atoms, complementing the scanning tunneling microscopy/spectroscopy and photoelectron spectroscopy (XPS). Examining Rh and Pt surfaces with and without adatoms and graphite surface with and without atomic vacancies, we confirmed that: i) bonds between undercoordinated atoms become shorter and stronger; ii) subjective polarization happens to the valence electrons of defects or adatoms by the densely entrapped bonding electrons, which in turn screens and splits the crystal field and hence the core band of the specimen.

Published
2011

5. Zone-resolved photoelectronic scoping of the local bonding and electronic dynamics at the graphite skin with and without atomic vacancy and the associated graphene edge states

Author

Sun, Chang Q., Nie, Yanguang, Pan, Jisheng, Zhang, Xi, Ma, S. Z., Wang, Yan, and Zheng, Weitao

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

A zone-resolved photoelectron spectroscopy (ZPS) has enabled us to gain the local and quantitative information and hence confirm our theoretical expectations on the bonding and electronic dynamics at graphite skin with and without atomic vacancy defects. The ZPS study has revealed: i) the 1s energy level of an isolated carbon atom is located at 282.57 eV, which shifts by 1.32 eV deeper upon diamond bulk formation; ii) the graphite surface bonds contract by 18% with 165% gain in energy compared with the C-C bond in the bulk diamond; the surface C 1s energy shifts 2.08 eV deeper from the 1s level of an isolated carbon atom; and iii) the defect bonds are ~26% shorter and 215% stronger with the binding energy shift of ~2.85 eV. An additional polarization peak centered at 1.28 eV below the C 1s level presents when the vacancy is formed. Associated with the scanning tunneling microscopy/spectroscopy observations and density functional theory calculations, the ZPS measurements clarify, for the first time, that the graphitic Dirac-Fermi polarons at atomic vacancy or graphene zigzag edge arise from the polarization of the unpaired dangling-bond electrons by the undercoordination-induced local densification and quantum entrapment of the bonding electrons.

Published
2011

6. Purified graphite surface and vacancy states: undercoordination-induced quantum trap depression and lone pi-electron polarization

Author

Sun, Chang Q, Nie, Yanguang, Pan, Jisheng, and Zheng, Weitao

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

We present a simple approach for purifying graphite surface and vacancy states using an angle-resolved x-ray photoelectron residual spectroscopy (XPS). Complementing the discoveries of Ugeda et al [Phys Rev Lett 104, 096804 (2010)], outcomes conform the BOLS theory [Sun, Prog Solid State Chem 35, 1-159 (2007)] expectation and the recent findings that the shorter and stronger bonds between undercoordinated atoms induce local strain and quantum potential depression with an association of local densification of energy and core electrons. The shorter atomic distance and the densely and deeply trapped bonding and core charges polarize in turn the unpaired pi-electrons nearby vacancy, giving rise to the high protrusions and the Dirac EF states as observed. The quantum trap depression and the screening due to the polarized EF states split the crystal potential and hence the extra XPRS C 1s states., Comment: 13 draft pages, 3 figures

Published
2010

19. Coordination-Resolved Electron Spectrometrics

Author

Liu, Xinjuan, primary, Zhang, Xi, additional, Bo, Maolin, additional, Li, Lei, additional, Tian, Hongwei, additional, Nie, Yanguang, additional, Sun, Yi, additional, Xu, Shiqing, additional, Wang, Yan, additional, Zheng, Weitao, additional, and Sun, Chang Q, additional

Published
2015
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23. Effects of nonmetal doping on electronic structures of NaNbO3 based on hybrid density functional calculation.

Author

Shi, Haifeng, Lan, Benyue, Zhang, Chengliang, Ye, Enjia, Nie, Yanguang, and Bian, Baoan

Subjects
SEMICONDUCTOR doping, ANIONS, NIOBATES, DENSITY functional theory, VALENCE bands, BAND gaps
Abstract

The influences of a series of anion doping on the electronic structures of sodium niobate (NaNbO3) have been systematically investigated by density functional theory (DFT) calculations with the hybrid B3LYP functional. As for B(C,P)-doped NaNbO3, the isolated B 2 p (C 2 p, P 3 p) states were formed above the valence band maximum (VBM) of NaNbO3, which were too weak to mix with O 2 p states and thus produced band gap narrowing. While the band gap of NaNbO3 was slightly narrowed after F doping. As for S-doped NaNbO3, the S 3 p states mixed with O 2 p states well and thus reduced the band gap energy. According to the calculation results, we tentatively put forward that S doping would be appropriate for single anion doping NaNbO3, while the B(C,P) elements would be suitable candidates for co-doping NaNbO3. [ABSTRACT FROM AUTHOR]

Published
2016
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38. K2SO4 nanowires a good nanostructured template

Author

Chen, Haiyong, primary, Zhang, Jiahua, additional, Wang, Xiaojun, additional, Nie, Yanguang, additional, Gao, Shiyong, additional, Zhang, Mingzhe, additional, Ma, Yanmei, additional, Dai, Quanqin, additional, Li, Dongmei, additional, Kan, Shihai, additional, and Zou, Guangtian, additional

Published
2006
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39. A general method for fabricating nanorods

Author

Chen, Haiyong, primary, Nie, Yanguang, additional, Wang, Lijing, additional, Zhang, Jiahua, additional, Dong, Fengxia, additional, Dai, Quanqin, additional, Lu, Hongliang, additional, Gao, Shiyong, additional, Li, Dongmei, additional, Kan, Shihai, additional, and Zou, Guangtian, additional

Published
2006
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40. Atomic-Layer- and Crystal-Orientation-Resolved 3d5/2Binding Energy Shift of Ru(0001) and Ru(101̅0) Surfaces

Author

Wang, Yan, Nie, Yanguang, Wang, Lingling, and Sun, Chang Q.

Abstract

Theoretical reproduction of the Ru(0001) and Ru(101̅0) surface XPS profiles has led to the following information: (i) the 3d5/2energy level of an isolated Ru atom (E3d(z= 0) = 275.883 ± 0.002 eV); (ii) the energy shift of the 3d5/2energy (ΔE3d(z= 12) = 3.661 eV) from the E3d(0) upon bulk formation; (iii) the effective zvalues of the surface sublayers; (iv) the coordination (z) dependence of the energy shift: E3d(z) = ⟨E3d(0)⟩ + ΔE3d(12)cz−1= 275.883 ± 0.002 + 3.661/cz(eV), with cz= 2/{1 + exp[(12 − z)/(8z)]} being the z-dependent bond contraction coefficient; (v) the z-dependent lattice strain, binding energy density gain, and atomic cohesive energy remnant in the surface layers; and importantly, (vi) the physical origin for the surface-induced positive core-level shift. It has been clarified that the binding energy shift arises from the perturbation in the Hamiltonian by the shorter and stronger bonds between undercoordinated atoms. The developed approach should enhance the power of XPS for gaining information as such that is beyond the scope of conventional approaches.

Published
2010
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41. Structural transition induced by the release of residual stress in the complex of cubic and monoclinic Gd2O3:Eu nanoparticles

Author

Gao, Shiyong, Lu, Hongliang, Nie, Yanguang, Chen, Haiyong, Xu, Dan, Dai, Quanqin, Zhang, Jiahua, Gao, Chunxiao, Kan, Shihai, Li, Dongmei, and Zou, Guangtian

Subjects
*RESIDUAL stresses, *DEFORMATIONS (Mechanics), *HEAT treatment of metals, *STRAINS & stresses (Mechanics)
Abstract

Abstract: The Photoluminescence (PL) spectra of Gd2O3:Eu composed of cubic and monoclinic structure were collected on November 2003 and June 2006, respectively. The results show that a portion of cubic Gd2O3 transforms into monoclinic after the sample was left as it is for two years; and the 5D1–7FJ emission of Eu3+ in cubic host was enhanced in this released complex. Considering the high pressure behavior of Gd2O3, we think this structural transition is due to the sample that endures a process of press and release while the residual stress is released slowly. [Copyright &y& Elsevier]

Published
2007
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42. K2SO4 nanowires a good nanostructured template

Author

Chen, Haiyong, Zhang, Jiahua, Wang, Xiaojun, Nie, Yanguang, Gao, Shiyong, Zhang, Mingzhe, Ma, Yanmei, Dai, Quanqin, Li, Dongmei, Kan, Shihai, and Zou, Guangtian

Subjects
*NANOSTRUCTURED materials, *NANOWIRES, *RADIATION, *ELECTRIC conductivity
Abstract

Abstract: K2SO4 nanowires with the width of were fabricated by ice-subliming method. Under the heat radiation, the surface of K2SO4 nanowires presented ordering K2SO4 dots of 3.5 nm and arrays of narrow wires with the width of 3 nm due to the remnant H2O molecules are released. Using these K2SO4 nanowires as the substrate, ZnO nanowires were also fabricated by vapor-phase deposition. [Copyright &y& Elsevier]

Published
2006
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