Regensburg 2013 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 16: Theory: Metal-insulator transitions / Electronic structure calculations
HL 16.1: Talk
Monday, March 11, 2013, 15:30–15:45, H13
Robust Nodal Structure of Landau Level Wave Functions Revealed by Fourier Transform Scanning Tunneling Spectroscopy — K Hashimoto1,2, T Champel3, S Florens4, C Sohrmann5, J Wiebe6, Y Hirayama1,2, •RA Römer5, R Wiesendanger6, and M Morgenstern7 — 1Tohoku University, Sendai, Japan — 2JST, ERATO Nuclear Spin Electronics Project, Sendai 980-8578, Japan — 3Universite Joseph Fourier Grenoble I / CNRS UMR 5493, Grenoble, France — 4CNRS and Universite Joseph Fourier, Grenoble, France — 5University of Warwick, Coventry, UK — 6Institute of Applied Physics, Hamburg University, Hamburg, Germany — 7RWTH Aachen University, Aachen, Germany
Scanning tunneling spectroscopy is used to study the real-space local density of states (LDOS) of a two-dimensional electron system in magnetic field, in particular within higher Landau levels (LL). By Fourier transforming the LDOS, we find a set of n radial minima at fixed momenta for the nth LL. The momenta of the minima depend only on the inverse magnetic length. By comparison with analytical theory and numerical simulations, we attribute the minima to the nodes of the quantum cyclotron orbits, which decouple in Fourier representation from the random guiding center motion due to the disorder. Adequate Fourier filtering reveals the nodal structure in real space in some areas of the sample with relatively smooth potential disorder.