Interplay Between Electron Over-Heating and ac Josephson Effect

TL;DR

This paper investigates how electron over-heating affects the ac Josephson effect in high-critical current Josephson junctions under microwave excitation, revealing a significant influence on Shapiro steps and device dynamics.

Contribution

It introduces an extended resistively shunted junction model that incorporates thermal effects, demonstrating the impact of electron over-heating on ac Josephson phenomena.

Findings

Electron over-heating causes hysteresis in voltage-current characteristics.

Over-heating significantly alters the evolution of Shapiro steps.

Thermal modeling explains the strong electron over-heating observed.

Abstract

We study the response of high-critical current proximity Josephson junctions to a microwave excitation. Electron over-heating in such devices is known to create hysteretic dc voltage-current characteristics. Here we demonstrate that it also strongly influences the ac response. The interplay of electron over-heating and ac Josephson dynamics is revealed by the evolution of the Shapiro steps with the microwave drive amplitude. Extending the resistively shunted Josephson junction model by including a thermal balance for the electronic bath coupled to phonons, a strong electron over-heating is obtained.