Prospecting for the superfluid transition in electron-hole coupled quantum wells using Coulomb drag

TL;DR

This paper proposes using Coulomb drag measurements to detect precursor signs of superfluid transition in electron-hole quantum wells, showing that drag resistivity diverges near the critical temperature due to pairing fluctuations.

Contribution

It introduces a novel method to identify superfluid transition precursors via Coulomb drag and predicts a measurable divergence in drag resistivity above the transition temperature.

Findings

Drag resistivity $ ho_{21}$ is significantly enhanced above $T_c$

$ ho_{21}$ diverges logarithmically as $T o T_c^+$

Enhancement in $ ho_{21}$ is detectable at temperatures well above $T_c$

Abstract

I investigate the possibility of using Coulomb drag to detect a precursor of the predicted (but as yet not definitively observed) superfluid transition in electron-hole coupled quantum wells. The drag transresisitivity $\rho_{21}$ is shown to be significantly enhanced above the transition temperature $T_c$ and to diverge logarithmically as $T\to T_c^+$, due to electron-hole pairing fluctuations which are somewhat analogous to the Maki-Thompson contribution to conductivity in metals above the superconducting $T_c$. The enhancement in $\rho_{21}$ is estimated to be detectable at temperatures much higher than $T_c$.