Charge-imbalance effects in intrinsic Josephson systems

TL;DR

This paper investigates charge-imbalance effects in intrinsic Josephson systems, demonstrating how nonequilibrium phenomena influence IV-curves and Shapiro steps, supported by experimental evidence and theoretical modeling.

Contribution

It provides experimental evidence of charge-imbalance effects in intrinsic Josephson systems and offers a theoretical explanation for these nonequilibrium phenomena.

Findings

Shift in Shapiro step voltage due to charge imbalance

Influence of current in one mesa on another's voltage

Experimental results align with recent nonequilibrium theory

Abstract

We report on two types of experiments with intrinsic Josephson systems made from layered superconductors which show clear evidence of nonequilibrium effects: 1. In 2-point measurements of IV-curves in the presence of high- frequency radiation a shift of the voltage of Shapiro steps from the canonical value hf/(2e) has been observed. 2. In the IV-curves of double-mesa structures an influence of the current through one mesa on the voltage measured on the other mesa is detected. Both effects can be explained by charge-imbalance on the superconducting layers produced by the quasi-particle current, and can be described successfully by a recently developed theory of nonequilibrium effects in intrinsic Josephson systems.