Intermittent Josephson effect with feedback voltage and temperature oscillations in graphite-coated nanocapsules with superconducting TaC core

TL;DR

This paper reports the observation of an intermittent Josephson effect characterized by voltage and temperature oscillations in graphite-coated TaC nanocapsules, revealing complex non-equilibrium superconducting phenomena.

Contribution

It introduces the first observation of voltage and temperature oscillations due to Josephson effects in graphite-coated TaC nanocapsules near 2 K, highlighting non-equilibrium superconducting behavior.

Findings

Voltage and temperature oscillations observed near 2 K.

Oscillations linked to non-equilibrium conditions in Josephson junctions.

Phenomenon occurs in a granular TaC/carbon/TaC framework with Mott transition.

Abstract

An intermittent Josephson effect in the form of voltage and temperature oscillations in the voltage - current curves near 2 K is observed in pellets consisting of superconducting TaC nanocapsules coated with graphite. This phenomenon is attributed to non-equilibrium conditions, when Cooper pairs across a junction, which stimulate the emission of photons and the feedback temperature change of the junction. It occurs in a three-dimensional granular framework composed of TaC/carbon/TaC tunneling junctions with a Mott metal-insulator transition, below the critical temperature Tc of non-ideal type-II superconductor TaC.