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

Angle-resolved photoemission measurements of the Fermi surfaces of several surface localized states of clean and hydrogen-covered W(110) 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.