Nonlocal thermoelectricity in a topological Andreev interferometer

TL;DR

This paper explores a phase-tunable nonlocal thermoelectric effect in a topological Josephson junction, driven by helical edge states and Andreev interference, without external magnetic fields.

Contribution

It introduces a novel mechanism for nonlocal thermoelectricity in topological junctions, controllable via Josephson phase difference without magnetic fields.

Findings

Nonlocal Seebeck coefficient of a few microvolts per Kelvin.

Thermoelectric response tunable by Josephson phase difference.

Effect relies on helical edge states and Andreev interferometry.

Abstract

We discuss the phase dependent nonlocal thermoelectric effect in a topological Josephson junction in contact with a normal-metal probe. We show that, due to the helical nature of topological edge states, nonlocal thermoelectricity is generated by a purely Andreev interferometric mechanism. This response can be tuned by imposing a Josephson phase difference, through the application of a dissipationless current between the two superconductors, even without the need of applying an external magnetic field. We discuss in detail the origin of this effect and we provide also a realistic estimation of the nonlocal Seebeck coefficient that results of the order of few $\mu V/K$.