Berlin 2012 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 18: Spin-orbit interaction

O 18.1: Vortrag

Montag, 26. März 2012, 16:00–16:15, A 060

Detection of the spin-orbit splitting at the β–Bi/Si( 111 )-√3 × √3 surface by scanning tunneling spectroscopy — •Patrick Reissner, Paolo Sessi, and Matthias Bode — Physikalisches Institut, Experimentelle Physik II, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany

The √3 × √3 reconstruction formed by the adsorption of Bi on the Si( 111 ) surface has been recently reported to show a giant Rashba-Bychkov (RB) effect. Photoemission studies have highlighted its complex band structure consisting of multiple spin split bands with nontrivial spin texture [1]. Nevertheless a microscopic characterization is still missing. Here, we report on a combined STM/STS study of Bi/Si( 111 ) performed at cryogenic temperature. We show how it is possible, by means of STS, to locally detect the strength of the RB-splitting. Concerning occupied states, our results are in agreement with previously reported experiments. For unoccupied states, not accessible by standard photoemission techniques, we also observe spectroscopic features that are assigned to RB spin split states. Finally, by taking advantage of the high spatial resolution of STM, the influence of defects on the local density of states is discussed.
[1] K. Sakamoto et al., PRL 103 , 156801 (2009)