Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 26: Spin-controlled Transport II

HL 26.8: Vortrag

Dienstag, 23. März 2010, 16:00–16:15, H14

Scanning tunneling spectroscopy of a dilute two-dimensional electron system exhibiting Rashba spin splitting — •Stefan Becker, Marcus Liebmann, and Markus Morgenstern — II. Physikalisches Institut B, RWTH Aachen and JARA-FIT, 52074 Aachen

Using scanning tunneling spectroscopy (STS) at 5 Kelvin in B-fields up to 7 Tesla, we investigate the local density of states of a two-dimensional electron system (2DES) created by Cs adsorption on p-type InSb(110). Cs induces a large band bending on the p-type InSb(110) surface creating a 2DES in the inversion layer, which in contrast to previous STS studies exhibits a 2D Fermi level. The 2DES shows standing waves with wave numbers in accordance with theory. In a perpendicular magnetic field the percolating drift states of the quantum hall transition are observed within the disorder broadened Landau levels. Using a highly doped sample we achieve a steep band bending potential showing Landau levels with a beating pattern attributed to Rashba spin splitting. Due to the high electric field of the potential, a large Rashba parameter in the order of α = 7 × 10⁻¹¹  eV · m can be estimated. A simulation of the density of states using this value reproduces the observed beating pattern very well.