Regensburg 2007 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 47: Transport in high magnetic field/quantum-Hall-effect

HL 47.7: Talk

Thursday, March 29, 2007, 17:15–17:30, H14

Phonon Drag in High Landau Levels — •Christian Joas and Jürgen Dietel — Institut für theoretische Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin

The information provided by drag measurements in bilayer quantum Hall systems subjected to a perpendicular magnetic field is complementary to conventional transport measurements and thus constitutes a valuable additional tool for the investigation of quantum Hall systems. Most experimental and theoretical work is focused on the study of Coulomb drag, which, for small interlayer separations, yields the dominant contribution to the drag conductivity. For larger interlayer separations, also phonon-mediated interlayer interactions become relevant. In contrast to the case of Coulomb drag, where the drag conductivity is dominated by small momentum tranfers between the layers, the momentum transfers involved in phonon drag can be of the order of the Fermi momentum. By generalizing the linear response theory of Coulomb drag [1] to arbitrary momentum tranfers, we derive a theory of phonon drag in high Landau levels and present analytical and numerical results for the phonon-mediated contribution to the drag conductivity. We show that the temperature dependence of phonon drag differs strongly from the behavior of Coulomb drag. We also compare our results with experiments for phonon drag at zero magnetic field [2].

[1] I. V. Gornyi, A. D. Mirlin, and F. von Oppen, Phys. Rev. B 70, 245302 (2004). [2] T. J. Gramila, J. P. Eisenstein, A. H. MacDonald, L. N. Pfeiffer, and K. W. West, Phys. Rev. Lett. 66, 1216 (1991).