Regensburg 2004 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 14: Symposium Quanten-Hall-Systeme

HL 14.2: Vortrag

Dienstag, 9. März 2004, 10:45–11:15, H15

Oscillatory photoconductivity of a 2D electron gas in magnetic field — •D.G. Polyakov¹, I.A. Dmitriev¹, M.G. Vavilov², I.L. Aleiner³, and A.D. Mirlin^1,4 — ¹Institut für Nanotechnologie, Forschungszentrum Karlsruhe, 76021 Karlsruhe — ²Physics Dept., Massachusetts Institute of Technology, Cambridge, MA 02139, USA — ³Physics Dept., Columbia University, New York, NY 10027, USA — ⁴Institut für Theorie der kondensierten Materie, Universität Karlsruhe, 76128 Karlsruhe

An intriguing development in the study of magnetotransport in high-mobility 2DEGs was the observations by Zudov et al. and by Mani et al. of magnetooscillations of the photoconductivity, evolving with increasing microwave power into zero-resistance states. We discuss the nature of the oscillations and develop theory which is in good agreement with the experimental data. The most important mechanism of the oscillations [1,2] is related to a radiation-induced change of the electron distribution function. We consider nonlinear effects, with respect to both the dc field and the microwave power, as well as the temperature dependence due to the inelastic relaxation. We also study [3] the oscillations governed by quasiclassical memory effects. For low B, this mechanism, in combination with microwave-dependent screening, may dominate over that based on the Landau quantization. [1] I.A.Dmitriev, A.D.Mirlin, and D.G.Polyakov, cond-mat/0304529; [2] I.A.Dmitriev, M.G.Vavilov, I.A.Aleiner, A.D.Mirlin, and D.G.Polyakov, cond-mat/0310668; [3] I.A.Dmitriev, A.D.Mirlin, and D.G.Polyakov, to be published.