Electric field dependence of thermal conductivity of a granular superconductor: Giant field-induced effects predicted

TL;DR

This paper predicts giant electric field-induced effects on the thermal conductivity of granular superconductors using a 3D Josephson junction array model, highlighting significant nonlinear enhancements at low temperatures.

Contribution

It introduces a novel theoretical model predicting large electric field effects on thermal conductivity in granular superconductors, including a giant nonlinear enhancement.

Findings

Electric field decreases linear thermal conductivity.

Giant enhancement (up to 500%) of nonlinear thermal conductivity predicted.

Effects potentially observable in experiments on granular superconductors.

Abstract

The temperature and electric field dependence of electronic contribution to the thermal conductivity (TC) of a granular superconductor is considered within a 3D model of inductive Josephson junction arrays. In addition to a low-temperature maximum of zero-field TC K(T,0) (controlled by mutual inductance L_0 and normal state resistivity R_n), the model predicts two major effects in applied electric field: (i) decrease of the linear TC, and (ii) giant enhancement of the nonlinear (i.e., grad T-dependent) TC with [K(T,E)-K(T,0)]/K(T,0) reaching 500% for parallel electric fields E=E_T (E_T=S_0|grad T| is an "intrinsic" thermoelectric field). A possiblity of experimental observation of the predicted effects in granular superconductors is discussed.