Rashba-type spin splitting at Au(111) beyond the Fermi level: the other part of the story

Wissing S N P, Eibl C, Zumbülte A, Schmidt A B, Braun J, Minár J, Ebert H, Donath M

Abstract

We present a combined experimental and theoretical study of spin-orbitinducedspin splittings in the unoccupied surface electronic structure of the prototypicalRashba system Au(111). Spin- and angle-resolved inverse-photoemission measurementsreveal a Rashba-type spin splitting in the unoccupied part of the L-gap surface state.With increasing momentum parallel to the surface, the spectral intensity is loweredand the spin splitting vanishes as the surface state approaches the band-gap boundary.Furthermore, we observe significantly spin-dependent peak positions and intensities fortransitions between unoccupied sp-like bulk bands. Possible reasons for this behaviorare considered: initial and final-state effects as well as the transition itself, which iscontrolled by selection rules depending on the symmetry of the involved states. Basedon model calculations, we identify the initial states as origin of the observed Rashbatypespin effects in bulk transitions.