Berlin 2005 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 7: Transporteigenschaften
HL 7.3: Vortrag
Freitag, 4. März 2005, 11:15–11:30, TU P-N226
Magneto-transport measurements on evenly curved Hall bars — •Olrik Schumacher1, Stefan Mendach1, Matthias Holz2, Holger Welsch1, Christian Heyn1 und Wolfgang Hansen1 — 1Institut für Angewandte Physik, Universität Hamburg, Jungiusstr. 11, 20355 Hamburg — 2I. Institut für Theoretische Physik, Universität Hamburg, Jungiusstr. 9, 20355 Hamburg
We present transport measurements on evenly curved Hall bars integrated into InGaAs-microtubes. The method of self-rolling strained semiconductor double layers enables to build tubes with tuneable radii [1,2]. By the use of an optimized epitaxial layer design combined with a special lithographic procedure we are able to fabricate GaAs/InGaAs-microtubes containing a two-dimensional electron system (2-DES) in the tube walls. This opens up the possibility to perform transport measurements on evenly curved Hall bars with a strongly modulated magnetic field component perpendicular to the 2-DES plane. Transport measurements on such curved Hall bars with current direction along the curvature exhibit pronounced Shubnikow-de Haas oscillations which are found to be associated with the maximum perpendicular magnetic field component between the voltage contacts. Furthermore, we find a magnetic field inversion asymmetry depending on the perpendicular field component distribution along the curved Hall bar. For small magnetic fields we explain this asymmetry in classical terms using numerical simulations, for higher magnetic fields the Landauer Büttiker formalism is applied.
[1] V. Ya. Prinz et al., Physica E 6 (2000) 828-831
[2] O. G. Schmidt, K. Eberl, Nature 410 (2001) 168