Coulomb drag in compressible quantum Hall states

Iddo Ussishkin; Ady Stern

doi:10.1103/PhysRevB.56.4013

paper

Coulomb drag in compressible quantum Hall states

arXiv:cond-mat/9701135 · doi:10.1103/PhysRevB.56.4013

Abstract

We consider the Coulomb drag between two layers of two-dimensional electronic gases subject to a strong magnetic field. We first focus on the case in which the electronic density is such that the Landau level filling fraction $ν$ in each layer is at, or close to, $ν = 1/2$ . Discussing the coupling between the layers in purely electronic terms, we show that the unique dependence of the longitudinal conductivity on wave-vector, observed in surface acoustic waves experiments, leads to a very slow decay of density fluctuations. Consequently, it has a crucial effect on the Coulomb drag, as manifested in the transresistivity $ρ_{D}$ . We find that the transresistivity is very large compared to its typical values at zero magnetic field, and that its temperature dependence is unique -- $ρ_{D} \propto T^{4/3}$ . For filling factors at or close to $1/4$ and $3/4$ the transresistivity has the same $T$ -dependence, and is larger than at $ν = 1/2$ . We calculate $ρ_{D}$ for the $ν = 3/2$ case and propose that it might shed light on the spin polarization of electrons at $ν = 3/2$ . We compare our results to recent calculations of $ρ_{D}$ at $ν = 1/2$ where a composite fermion approach was used and a $T^{4/3}$ -dependence was obtained. We conclude that what appears in the composite fermion language to be drag induced by Chern-Simons interaction is, physically, electronic Coulomb drag.

arXiv comment11 pages, REVTeX with two Postscript figures

Coulomb drag in compressible quantum Hall states

Abstract

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