| AVS 60th International Symposium and Exhibition | |
| Magnetic Interfaces and Nanostructures | Monday Sessions |
| Session MI-MoM |
| Session: | Topological Materials, Rashba Systems, and Heusler Alloys |
| Presenter: | S.N.P. Wissing, Westfälische Wilhelms-Universität Münster, Germany |
| Authors: | S.N.P. Wissing, Westfälische Wilhelms-Universität Münster, Germany A.B. Schmidt, Westfälische Wilhelms-Universität Münster, Germany Chr.R. Ast, Max-Planck-Institut für Festkörperforschung Stuttgart, Germany H. Mirhosseini, Max-Planck-Institut für Mikrostrukturphysik Halle, Germany J. Henk, Martin-Luther-Universität Halle-Wittenberg, Germany M. Donath, Westfälische Wilhelms-Universität Münster, Germany |
| Correspondent: | Click to Email |
The spin topology of electronic bands, caused by spin-orbit interaction in Rashba systems and topological insulators, is subject of current debate. In some cases, the experiments findings are in conflict with theoretical predictions. In this contribution, we will discuss this issue with respect to the spin-resolved unoccupied electronic structure of the surface alloy Bi/Ag(111) (√3×√3)R30°.
Surface alloys of heavy elements on noble metal fcc(111) surfaces exhibit surface states with giant Rashba-type spin splittings. Therefore, they have been investigated thoroughly in recent years, in particular their occupied band structure by spin- and angle-resolved photoemission. Above the Fermi level, however, there is basically a blank area on the E(k║) map.
We present a study on the unoccupied electronic structure of Bi/Ag(111) with spin- and angle-resolved inverse photoemission. Above the Fermi level, we identified several states with distinct spin dependence. We determined their nature concerning symmetry, bulk vs. surface character, energy vs. momentum dispersion, and spin dependence. In particular, we focused our attention to the spin character of the mj=1/2 surface state. While theoretical calculations [1] predict a complex spin topology, where the spin polarization changes sign at the band maximum, our experimental findings indicate a spin splitting compatible with the classical Rashba model. To shed more light on this issue, we investigated the spin topology with the help of first-principles electronic-structure calculations. We will discuss the difficulty of assigning a pure spin character to a particular Rashba band, especially in view of the experimental geometry, which itself influences the measured spin character.
[1] G. Bihlmayer et al., Phys. Rev. B 75, 195414 (2007)