Berlin 2012 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 32: Transport Properties I (mainly Spin Physics and Magnetic Fields)
HL 32.7: Talk
Tuesday, March 27, 2012, 11:45–12:00, EW 203
Electron Transport in Side-Gated Quantum-Point Contacts on InAs/InAlGaAs Heterostructures — •Jens S. Kienitz1, Hauke Lehmann1, Christian Heyn1, Dirk Reuter2, Andreas D. Wieck2, Ulrich Merkt1, and Jan Jacob1 — 1Universität Hamburg, Institut für Angewandte Physik, Jungiusstraße 11, 20355 Hamburg — 2Ruhr-Universität Bochum, Lehrstuhl für Angewandte Festkörperphysik, Universitätsstraße 150, 44780 Bochum
Quantum-point contacts exhibiting conductance quantization of quasi one-dimensional electron systems have been studied extensively in GaAs/GaAlAs heterostructures [1], but not so in InAs/InAlGaAs heterostructures. The spin-orbit interaction in InAs is much stronger than in GaAs. Thus for applications in spintronics InAs is the material of choice. Nevertheless spin-dependent phenomena are only visible when few or just one transport modes contribute. In order to be able to count the number of occupied transport modes, well-defined conductance steps are mandatory. We define quantum-point contacts by side gates of different widths along InAs quantum wires and of different distances to these wires. Transport measurements at different temperatures between 15 mK and 4 K in high magnetic fields are presented. They hint at a stronger quantization for lower temperatures and higher magnetic fields. [1] B. van Wees et al., Phys. Rev. Lett. 60, 848 (1988)