Parts | Days | Selection | Search | Downloads | Help
O: Fachverband Oberflächenphysik
O 48: Focused Session: Spin-Orbit Interaction at Surfafces: From the Rashba Effect to Topological States of Matter I
O 48.6: Talk
Thursday, March 26, 2009, 12:30–12:45, HSZ 02
Rashba effect in unoccupied states: Two-photon photoemission experiments and first-principles calculations for Bi/Cu(111) — Ping Yu, Cheng-Tien Chiang, Aimo Winkelmann, Hossein Mirhosseini, Arthur Ernst, Sergey Ostanin, •Jürgen Henk, and Jürgen Kirschner — Max Planck Institute of Microstructure Physics, Halle, Germany
Surface alloys of Bi and noble metals on fcc(111) surfaces exhibit Rashba-split occupied spz surface states which have been thoroughly investigated by photoemission experiments and electronic-structure calculations. Their unmatched splitting is attributed to the interplay between an in-plane potential gradient and the conventional out-of-plane image-potential gradient. However, the splitting of a set of pxpy surface states remained unresolved so far because these unoccupied states cannot be accessed by conventional photoemission.
By angle-resolved two-photon photoemission experiments and first-principles calculations we study in detail the unoccupied pxpy states on √3×√3R30∘-Bi/Cu(111). Their experimental dispersion in the relevant energy range, band maxima (at EF + 1.4 eV), and momentum offset (0.03 Å−1) agree with the theoretical predictions. Due to their symmetry, these states are expected to be particularly responsive to an in-plane gradient. The abovementioned mechanism and its implications on dispersion and spin polarization are discussed.