Sign of the Rashba parameter in image-potential states

This is the authors' abstract. We don't add key points for this paper.

Image-potential surface states are simple model systems, where spin-dependent effects can be studied in view of spintronic applications. The Rashba effect in surface states at high- Z materials is related to both the strong spin-orbit interaction in heavy atoms and the orbital angular momentum arising from the inversion-symmetry breaking at the surface. Our study on image-potential states at Bi 2 Se 3 and Bi 2 Te 3 showcases that the orbital angular momentum causes an intrinsically reversed Rashba parameter α R ≈ − 100 meV Å , i.e., a reversed spin splitting compared with the prototypical Rashba-split Au(111) crystal-induced surface state. We present a consistent picture of spin-resolved experimental data from inverse photoemission and three-photon photoemission together with calculations from density-functional theory and many-body perturbation theory.