Dresden 2006 – scientific programme

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TT: Tiefe Temperaturen

TT 21: Transport: Nanoelectronics II - Spintronics and Magnetotransport - Part 2

TT 21.8: Talk

Tuesday, March 28, 2006, 18:15–18:30, HSZ 105

Magnetotransport along a barrier: multiple quantum interference of edge states — •Anatoli M. Kadigrobov, Mikhail V. Fistul, and Konstantin B. Efetov — Theoretische Physik III, Ruhr-Universität Bochum, D-44801 Bochum Germany

Transport in a two-dimensional electron gas subject to an external magnetic field is analyzed in the presence of a longitudinal barrier. Similar systems have been produced by using a split-gate technique or cleaved edge fabrication method. We show that quantum interference of the edge states bound by the longitudinal barrier results in a drastic change of the electron motion: the degenerate discrete Landau levels are transformed into an alternating sequence of energy bands and energy gaps. The spectrum є_n(p_x) is characterized by a nearly periodic dependence on the momentum p_x along the barrier. The width of the bands and the gaps can be tuned by the magnetic field and the gate voltage. These features of the electron spectrum should result in a high sensitivity of thermodynamic and transport properties of the 2D electron gas to external fields. In particular, we predict giant oscillations of the ballistic conductance and discuss nonlinear current-voltage characteristics, coherent Bloch oscillations and effects of impurities.