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Plumbene, with a structure similar to graphene, is expected to possess a strong spin–orbit coupling and thus enhances its superconducting critical temperature (Tc). In this work, a buckled plumbene‐Au Kagome superstructure grown by depositing Au on Pb(111) is investigated. The superconducting gap monitored by temperature‐dependent scanning tunneling microscopy/spectroscopy shows that the buckled plumbene‐Au Kagome superstructure not only has an enhanced Tc with respect to that of a monolayer Pb but also possesses a higher value than what owned by a bulk Pb substrate. By combining angle‐resolved photoemission spectroscopy with density functional theory, the monolayer Au‐intercalated low‐buckled plumbene sandwiched between the top Au Kagome layer and the bottom Pb(111) substrate is confirmed and the electron–phonon coupling‐enhanced superconductivity is revealed. This work demonstrates that a buckled plumbene‐Au Kagome superstructure can enhance superconducting Tc and Rashba effect, effectively triggering the novel properties of a plumbene. [ABSTRACT FROM AUTHOR]

The surface photovoltage (SPV) effect is key to the development of opto-electronic devices such as solar-cells and photo-detectors. For the prototypical transition metal dichalcogenide WSe2, core level and valence band photoemission measurements show that the surface band bending of pristine cleaved surfaces can be readily modified by adsorption with K (an electron donor) or C60 (an electron acceptor). Time-resolved pump-probe photoemission measurements reveal that the SPV for pristine cleaved surfaces is enhanced by K adsorption, but suppressed by C60 adsorption, and yet the SPV relaxation time is substantially shortened in both cases. Evidently, adsorbate-induced electronic states act as electron-hole recombination centers that shorten the carrier lifetime. [ABSTRACT FROM AUTHOR]

We have developed a soft x-ray time-resolved photoemission spectroscopy system using synchrotron radiation (SR) at SPring-8 BL07LSU and an ultrashort pulse laser system. Two-dimensional angle-resolved measurements were performed with a time-of-flight-type analyzer. The photoemission spectroscopy system is synchronized to light pulses of SR and laser using a time control unit. The performance of the instrument is demonstrated by mapping the band structure of a Si(111) crystal over the surface Brillouin zones and observing relaxation of the surface photo-voltage effect using the pump (laser) and probe (SR) method. [ABSTRACT FROM AUTHOR]

A new spin- and angle-resolved photoemission spectrometer was developed adopting the very-low-energy-electron-diffraction (VLEED)-type spin polarimeter. The Fe(001)p(1×1)–O film grown on MgO(001) crystal for the VLEED target yields significantly high spin-resolving power, the effective Sherman function of 0.40±0.02, with long lifetime and stability compared to the conventional Fe(001) target. Under the favor of high resolving power, approximately 100 times higher efficiency than that of conventional Mott-type spin polarimeter, the figure of merit of 1.9±0.2×10-2 was achieved. Owing to this high efficiency, high-energy resolution can be realized with this new spin-polarized photoemission spectrometer. The simplified ways of target preparation and revitalization make the VLEED spin polarimeter much more convenient and feasible for the spin-polarized photoemission spectroscopy. [ABSTRACT FROM AUTHOR]

Abstract: Si 2p core-level spectra (CLS) of Au adsorbed surface at various Au coverages were measured using photoemission spectroscopy. At very low Au coverage where identical Au nanoclusters randomly distribute on the surface, the Si 2p CLS are reasonably decomposed, which implies the dispersed electrostatic potentials induced by the Au nanoclusters are strongly screened so that the inhomogeneity of the underlying band-bending is negligible. However, at a higher Au coverage where a part of Au nanoclusters aggregate into the superstructure (), the Si 2p CLS cannot be fully decomposed but be reproduced by combination of the CLS obtained from a pure Au nanocluster phase and a phase. This indicates a strong band-bending inhomogeneity due to the partially aggregation of Au nanoclusters on the surface. [Copyright &y& Elsevier]

A small electron pocket composed of a metallic and parabolic surface-state band of Si(1 1 1)√ of 3×√ of 3-Ag was investigated in detail by high-resolution angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling spectroscopy (STS). The Fermi surface was a complete circle (Fermi ring), and the band dispersion was determined three dimensionally in energy–momentum space. The effective mass (m*) was extracted by a new method, two-dimensional (2D) fitting to the band dispersion, and compared with the results of conventional analyses of energy and momentum distribution curves (EDC and MDC). The EDC (MDC) analysis gave a m* value larger (smaller) than that obtained by the 2D fitting method by about 20%. The m* obtained by the 2D fitting was in good agreement with the value obtained by the STS measurements of electron standing waves, giving the most plausible value of m*=(0.13±0.03)me (me is the free-electron mass) for the parabolic band. [Copyright &y& Elsevier]

Carrier transport mechanism on Ge nanodot arrays formed on SiO2 monolayer covering over the Si surface is investigated by microscopic four-point-probe measurements combined with core-level photoemission spectroscopy and scanning tunneling microscopy. Different conduction natures are found depending on whether or not the nanodots and the substrate are directly connected by subnanometer-sized voids penetrating the SiO2 layer. In the presence of the voids, conductivity is regulated by the dot-size through quantum-size effect. [ABSTRACT FROM AUTHOR]

We measured the magnetoconductance of bare and √3×√3-Bi/Ag-terminated ultrathin Ag(111) films by the micro-four-point probe method as a function of the applied magnetic field. The experimental curves were analyzed by introducing the results of photoemission investigation and band-structure calculations into the Hikami-Larkin-Nagaoka formula, in order to derive the characteristic fields of the two systems. The formation of the Rashba-type surface alloy was found to reduce the spin-relaxation time in the ultrathin film significantly. [ABSTRACT FROM AUTHOR]