Thermoelectric properties of inversion symmetry broken Weyl semimetal-Weyl superconductor hybrid junctions

TL;DR

This paper theoretically analyzes the thermoelectric properties of a hybrid junction between an inversion symmetry broken Weyl semimetal and a Weyl superconductor, revealing unique thermal transport features and violations of the Wiedemann-Franz law.

Contribution

It introduces a detailed theoretical framework for thermoelectric effects in WSM-WSC hybrid structures, including the impact of interfacial barriers and temperature regimes.

Findings

Wiedemann-Franz law is violated near Weyl points at low temperatures.

Thermal conductance and thermoelectric coefficient show distinctive behaviors depending on barrier strength.

The study provides insights for designing mesoscopic thermoelectric devices using Weyl semimetals.

Abstract

We theoretically investigate the thermoelectric properties (electronic contribution) of a hybrid structure comprising of an inversion symmetry broken Weyl semimetal (WSM) and intrinsic Weyl superconductor (WSC) with $s$-wave pairing, employing the Blonder-Tinkham-Klapwijk formulation for non-interacting electrons. Our study unfolds interesting features for various relevant physical quantities such as the thermal conductance, the thermoelectric coefficient and the corresponding figure of merit. We also explore the effects of an interfacial insulating (I) barrier (WSM-I-WSC set-up) on the thermoelectric response in the thin barrier limit. Further, we compute the ratio of the thermal to the electrical conductance in different temperature regimes and find that the Wiedemann-Franz law is violated for small temperatures (below critical temperature $T_{c}$) near the Weyl points while it saturates to the Lorentz number, away from the Weyl points, at all temperatures irrespective of the barrier strength. We compare and contrast this behaviour with other Dirac material heterostructures and provide a detailed analysis of the thermal transport. Our study can facilitate the fabrication of mesoscopic thermoelectric devices based on WSMs.