Phase-sensitive thermoelectricity and long-range Josephson effect supported by thermal gradient

TL;DR

This paper predicts that in multi-terminal superconducting nanostructures, thermoelectric signals and Josephson currents are significantly enhanced by temperature gradients, with unique temperature and topology-dependent behaviors observable experimentally.

Contribution

It introduces a novel understanding of phase-sensitive thermoelectricity and long-range Josephson effects driven by thermal gradients in superconducting hybrid systems.

Findings

Thermoelectric signals and Josephson currents decay algebraically with temperature.

Non-trivial current-phase relations and $ ext{π}$-junction transitions are predicted.

Features are observable simultaneously in experiments.

Abstract

We demonstrate that thermoelectric signal as well as dc Josephson current may be severely enhanced in multi-terminal superconducting hybrid nanostructures exposed to a temperature gradient. At temperatures $T$ strongly exceeding the Thouless energy of our device both the supercurrent and the thermo-induced voltage are dominated by the contribution from non-equilibrium low energy quasiparticles and are predicted to decay slowly (algebraically rather than exponentially) with increasing $T$. We also predict a non-trivial current-phase relation and a transition to a $\pi$-junction state controlled by both the temperature gradient and the system topology. All these features are simultaneously observable in the same experiment.