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

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 $T_c$.