Coulomb Drag as a Probe of Quantum Hall Systems

Abstract

Experiments on Coulomb drag in double-layer systems in the quantum Hall regime have observed a number of surprises which were only partially understood for some time. The most striking observations are that Coulomb drag can become negative in the regime of high Landau levels and that its temperature dependence is non-monotonous. In this contribution, we review a theory of Coulomb drag in high Landau levels for the ballistic regime which is in good agreement with the experiments. Our starting point is the diagrammatic approach to drag, treating the interlayer interaction perturbatively and accounting for disorder within the self-consistent Born approximation. Our theory shows that drag in high Landau levels is an interplay of two contributions arising from different sources for particle-hole asymmetry, namely the curvature of the zero-field electron dispersion and the Landau-level density of states.Keywords60.00; 70.00; 80.00