Tschang-Uh Nahm

The occupied and unoccupied electronic structures of disordered ${\mathrm{Au}}_{x}{\mathrm{Pd}}_{1\ensuremath{-}x}$ alloys are studied by valence-band photoemission, bremsstrahlung isochromat spectroscopy (BIS), and x-ray absorption near-edge spectroscopy (XANES). The occupied partial spectral weights (PSW's) of Au $5d$ and Pd $4d$ states are obtained from the valence-band photoemission spectra using synchrotron radiation by taking the matrix-element effect into account. We use the Cooper minimu

It is found that a change of the photoionization matrix element with the binding energy in the valence band can cause a substantial discrepancy between the density of states and the photoemission spectrum for d-band metals and alloys even in the x-ray photoemission spectroscopy regime. This is the main cause of the controversial discrepancy between photoemission spectra and theoretical density of states predicted in the Korringa-Kohn-Rostoker coherent-potential approximation for Cu-Pd alloys, ra

The valence-band photoemission spectra of disordered ${\mathrm{Cu}}_{\mathit{x}}$${\mathrm{Pd}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$ alloys are measured with synchrotron radiation in the soft-x-ray regime. Taking advantage of the Cooper-minimum phenomenon of the Pd 4d photoionization cross section, we obtain Pd and Cu partial spectral weights of ${\mathrm{Cu}}_{\mathit{x}}$${\mathrm{Pd}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$ alloys at various compositions (x=0.1, 0.25, 0.5, 0.75, 0.9) using the

The valence-band photoemission spectra of disordered ${\mathrm{Ni}}_{\mathit{x}}$${\mathrm{Pt}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$ and ${\mathrm{Cu}}_{\mathit{x}}$${\mathrm{Pt}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$ alloys have been measured with synchrotron radiation. Using the Cooper minimum phenomenon of the Pt 5d electron photoionization cross section and taking the matrix-element effect into account, we obtain experimental partial spectral weights (PSW's) of each constituent. For the Ni-

We present valence-band photoemission spectra of polycrystalline ${\mathrm{Cu}}_{\mathit{x}}$${\mathrm{Au}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$ (x=0.10, 0.25, 0.50, 0.75, 0.90) disordered binary alloys taken with variable incident-photon energies using synchrotron radiation. Taking advantage of the Cooper minimum phenomenon of the Au 5d band and taking proper account of the photoionization matrix element, we obtain experimental partial spectral weights for the alloys determined from the measur

We have studied magnetic and structural properties of ultrathin Fe lms grown on Pt(111) and Pd(111) substrates by using the in situ surface magneto-optic Kerr eect (SMOKE), X-ray photoelectron spectroscopy (XPS), and low-energy electron diraction (LEED). SMOKE measurements show that perpendicular magnetic anisotropy is present for an as-deposited 4.0 ML (monolayer) Fe lm on Pt(111) and partially induced by post-annealing at 450 K for a 2.0 ML Fe lm on Pd(111) surface. For thicker lms on Pd(111),

Received 28 September 1993DOI:https://doi.org/10.1103/PhysRevLett.72.794©1994 American Physical Society

Negative photoconductivity (NPC) was observed in n-ZnO/p-Si heterojunction diode grown by ultra-high vacuum sputtering method under nitrogen ambient. Under the illumination of ultra-violet light, positive photoconductivity was observed at low bias voltages, whereas NPC was observed at high bias voltages. The defect states in the ZnO layers grown on Si were analyzed by photoluminescence and deep level transient spectroscopy measurements. Two deep levels were measured at Ec-0.51 eV and Ec-0.54 eV,

In this study, Co2MnGa Heusler alloy (HA) ¯lms with signi¯cantly dierent structural orders were fabricated, and the in°uence of structural ordering on various physical properties was investigated. Co2MnGa ¯lms were deposited by °ash evaporation onto glass substrates at various substrate temperatures from 150 to 753 K. A disordered state of the ¯lms was achieved by using a vapor-quenching deposition at 150 K. Deposition at 623 K or post annealing of the disordered ¯lm at

The properties of transition metal dichalcogenides (TMDCs) are critically dependent on the dielectric constant of substrates, which significantly limits their application. To address this issue, we used a perfluorinated polyether (PFPE) self-assembled monolayer (SAM) with low surface energy to increase the van der Waals (vdW) gap between TMDCs and the substrate, thereby reducing the interaction between them. This resulted in a reduction in the subthreshold swing value, an increase in the photolu