Static charge-imbalance effects in intrinsic Josephson systems

TL;DR

This paper develops a microscopic theory to analyze how stationary current injection causes charge-imbalance effects in layered d-wave superconductors, impacting their current-voltage characteristics.

Contribution

It introduces a nonequilibrium Green function approach to quantify charge-imbalance in intrinsic Josephson systems, linking microscopic effects to experimental observations.

Findings

Charge-imbalance causes shifts in I-V curves.

The theory explains recent experimental results.

Charge-imbalance influences quasi-particle currents.

Abstract

Nonequilibrium effects created by stationary current injection in layered d-wave superconductors forming a stack of intrinsic Josephson junctions are studied. Starting from a nonequilibrium Green function theory we derive microscopic expressions for the charge-imbalance (difference between electron- and hole-like quasi-particles) on the superconducting layers and investigate its influence on the quasi-particle current between the layers. This nonequilibrium effect leads to shifts in the current-voltage curves of the stack. The theory is applied to the interpretation of recent current injection experiments in double-mesa structures.