Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 45: Electronic structure I
O 45.8: Vortrag
Mittwoch, 24. März 2010, 12:15–12:30, H33
Rashba Type Spin-Splitting in the Two-Dimensional Electron System Au/Ge(111) Studied by Angle-Resolved Photoemission — •Philipp Höpfner1, Jörg Schäfer1, Sebastian Meyer1, Christian Blumenstein1, Andrzej Fleszar2, Xiaoyu Cui3, Luc Patthey3, Werner Hanke2, and Ralph Claessen1 — 1Exp. Physik 4, Universität Würzburg — 2Theor. Physik 1, Universität Würzburg — 3Swiss Light Source, PSI, Villigen, Switzerland
The confinement of electrons in a single atomic adsorbate layer on a semiconductor surface presents an excellent playground for the study of electronic correlations in low dimensions. In this way, several intriguing two-dimensional electron systems (2DES) have been realized experimentally, such as e.g. the √3-reconstructions on (111) surfaces of Si and Ge. These systems are candidates for a spin-orbit splitting, due to the strong potential gradient at the surface, being in particular of the Rashba type.
In choosing heavy elements as adatoms, the spin-orbit interaction may play a significant role and one may ask what will happen to the Rashba splitting. We present results from angle-resolved photoelectron spectroscopy using synchrotron light of the metallic √3-Au/Ge(111) system. Two sets of metallic surface bands are observed, each of which appears to be split in pairs, originating from a Rashba type spin-splitting, as assigned by density functional theory calculations. Interestingly, the in-plane spin component varies across the Fermi surface. This metallic monolayer 2DES may represent a novel approach for spin injection into a semiconductor from a monolayer only.