Berlin 2012 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 91: Poster Session: Spintronics / Magnetic Semiconductors / Transport
HL 91.18: Poster
Thursday, March 29, 2012, 16:00–19:00, Poster D
Ballistic Hall voltage in an asymmetric cross junction — •Michael Szelong1, Ulrich Wieser1, Michael Knop1, Ulrich Kunze1, Dirk Reuter2, and Andreas Wieck2 — 1Lehrstuhl für Werkstoffe und Nanoelektronik, Ruhr-Universität Bochum — 2Lehrstuhl für angewandte Festkörperphysik, Ruhr-Universtät Bochum
We are interested in the influence of asymmetry of a cross junction on ballistic Hall voltage in linear and nonlinear transport regime. The junction consists of a straight 200 nm wide stem and two 140 nm wide branches which merge into the stem at an angle of 30∘ (60∘, 90∘) and serve as voltage probes. Devices with different stem widths are processed on a high-mobility GaAs/AlGaAs heterostructure with a two-dimensional electron density and mobility of n2D = 3.6 · 1011 cm−2 and µn = 8 · 105 cm2/Vs, respectively, resulting in a mean free path of about 8 µm at T = 4.2 K.
A current driven through the stem induces a Hall voltage which is expected to be dependent on the current polarity, larger where electrons flow easier into the tilted probes, smaller in the opposite case. Linear and nonlinear transport regimes as well as the transition are to be considered and compared to theoretical simulations, which are based on time-resolved propagation of electron wave packets.