Spin texture with a twist in momentum space for Tl/Si(111)

Stolwijk S., Sakamoto K., Schmidt A., Krüger P., Donath M.

Abstract

The electronic structure and spin texture around the M¯ point of Tl/Si(111)-(1×1) is investigated with spin- and angle-resolved inverse photoemission and density-functional theory. The Tl/Si(111)-(1×1) surface exhibits a surface-derived unoccupied state, which extends over the complete surface Brillouin zone. It is known for its giant spin-orbit-induced splitting and unique symmetry- and spin-orbit-induced spin landscape: a rotating spin pattern in momentum space along Γ¯K¯ and pure in-plane spin polarization along Γ¯M¯. Our results demonstrate how the M¯ point is encircled by this state. Its spin texture shows a peculiar twist, which reflects the C1h symmetry of the M¯ point.