Coulomb Drag in Normal Metals and Superconductors: Diagrammatic Approach

TL;DR

This paper develops a diagrammatic linear response formalism to analyze Coulomb drag in two-layer systems, incorporating disorder, interactions, and superconducting fluctuations, revealing significant effects near the superconducting transition.

Contribution

It introduces a comprehensive diagrammatic approach to Coulomb drag, including disorder, intralayer interactions, and superconducting fluctuations, extending previous methods.

Findings

Reproduces earlier results without intralayer correlations.

Calculates weak-localization corrections to drag coefficients.

Finds significant enhancement of drag in superconductor--superconductor systems.

Abstract

The diagrammatic linear response formalism for the Coulomb drag in two--layer systems is developed. This technique can be used to treat both elastic disorder and intralayer interaction effects. In the absence of intralayer electron--electron correlations we reproduce earlier results, obtained using the kinetic equation and the memory--function formalism. In addition we calculate weak--localization corrections to the drag coefficient and the Hall drag coefficient in a perpendicular magnetic field. As an example of the intralayer interaction effects we consider a situation where one (or both) layers are close to (but above) the superconducting transition temperature. Fluctuation corrections, analogous to the Aslamazov--Larkin corrections, to the drag coefficient are calculated. Although the fluctuation corrections do not enhance the drag coefficient for normal--superconductor systems, a dramatic enhancement is found for superconductor--superconductor structures.