Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 32: Transport Properties I (mainly Spin Physics and Magnetic Fields)
HL 32.5: Vortrag
Dienstag, 27. März 2012, 11:00–11:15, EW 203
Top Gates for InAs/InAlGaAs Heterostructures — •Jens S. Kienitz1, Lasse Cornils1, Till Benter1, Christian Heyn1, Katrin Groth1, Dirk Reuter2, Andreas 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
The intrinsic spin-Hall effect allows filtering of the electron spins in quasi one-dimensional electron systems. However the spin-Hall effect is only effective when the occupation of the transport modes is restricted to a small number. Hence control of the electron density is decisive. At the same time it is mandatory to keep the electron mobility high and to leave the spin-orbit coupling constant or to tune it in a precise and reproducible way. At liquid helium temperatures we determine from the Shubnikov-de Haas effect and the Hall effect the densities, the mobilities and the Rashba spin-orbit parameters [1] of electrons in InAs/InAlGaAs heterostructures with metallic top gates. The top gates are evaporated on insulating hydrogen silsesquioxane layers spun before onto the semiconductors. Our investigation includes InAs/InAlGaAs heterostructures with different innate electron densities and mobilities. The thickness of the InAlAs capping layer above the conducting InAs channel and the thickness of the insulating layer are also varied. [1] A. D. Wieck et al., Phys. Rev. Lett. 53, 493 (1984)