Experimental Fermi surfaces of clean and hydrogen-covered W(110)

Abstract

Angle-resolved photoemission measurements of the Fermi surfaces of several surface localized states of clean and hydrogen-covered W(l 10) are reported. Three hole orbits and one electron orbit have been characterized. The hole-orbit states are rapidly attenuated by hydrogen, while the electron-orbit states are shifted to higher binding energy resulting, initially, in an expansion of the Fermi surface, and ultimately, in its conversion to two hole orbits. These data represent the most detailed study of the behavior of the two-dimensional Fermi surface to date.

Surface states and spin density wave periodicity in Cr(110) films

“…We find surface bands with dispersion relations that are qualitatively similar to those characterized previously on W(110) and Mo(110) [16]- [19], although their photoemission intensity on Cr(110) is significantly lower and their widths are larger. The correlation between SDW periodicity and hydrogen-induced changes is associated with the evolution of a particular surface state-nesting vector and thus is related to singular behavior of the generalized spin susceptibility in the vicinity of the surface.…”

“…The correlation between SDW periodicity and hydrogen-induced changes is associated with the evolution of a particular surface state-nesting vector and thus is related to singular behavior of the generalized spin susceptibility in the vicinity of the surface. Similar to Mo(110) and W(110) [16,18,20], the Fermi contour of this band undergoes a topological transition upon hydrogen adsorption. We compare our measured dispersion relations to existing calculations [21,22] and find that some bands are well-described by theory, while others are not.…”

Frustrated H-Induced Instability of Mo(110)

“…For the clean (110) surfaces of W and Mo no indication of an anomaly is found, but this only appears when the surfaces are covered with a full layer of hydrogen. Nevertheless, a close link between the surface phonon anomalies and H vibrations seems to be ruled out, since the HAS spectra remain practically unchanged when deuterium is adsorbed instead of hydrogen [2,3].Angular resolved photoemission (ARP) studies have been performed by Kevan and coworkers [12][13][14] for clean and hydrogen covered W (110) and Mo (110). These studies give no evidence of the existence of parallel segments of the Fermi-surface contours separated by wave vectors comparable with the HAS determined critical wave vectors and thus there appeared to be compelling reason for abandoning the nesting mechanism as a possible origin of the anomalies seen in HAS.…”

“…Angular resolved photoemission (ARP) studies have been performed by Kevan and coworkers [12][13][14] for clean and hydrogen covered W (110) and Mo (110). These studies give no evidence of the existence of parallel segments of the Fermi-surface contours separated by wave vectors comparable with the HAS determined critical wave vectors and thus there appeared to be compelling reason for abandoning the nesting mechanism as a possible origin of the anomalies seen in HAS.…”

Photoemission study of Ce/Ta(110) and Ce/W(110) interfaces and the catalytic oxidation effect

“…After 7.5 Â, the W 4/ total intensity is reduced by a factor of 7. We also notice that the surface and "bulk" parts of the core level are well separated at all Ce coverages, without much change in their relative intensity (around 0.50/0.50, see Recently, Fermi surfaces of a few surface-localized states were mapped out on W(llO) [79]. In addition, a surface-localized feature observed near normal emission (F) at 1.18 eV binding energy was identified as a surface resonance state [80].…”