Coherent transport in homojunction between excitonic insulator and semimetal

TL;DR

This paper predicts that a junction between a semimetal and an excitonic insulator exhibits high resistance and low entropy production at low temperatures due to dissipationless exciton flow, differing from normal semiconductor junctions.

Contribution

It introduces a theoretical model showing unique transport properties in homojunctions involving excitonic insulators, highlighting the role of coherence in dissipationless exciton flow.

Findings

High resistance behavior at low temperatures

Low entropy production due to exciton flow

Distinct transport properties from normal semiconductor junctions

Abstract

From the solution of a two-band model, we predict that the thermal and electrical transport across the junction of a semimetal and an excitonic insulator will exhibit high resistance behavior and low entropy production at low temperatures, distinct from a junction of a semimetal and a normal semiconductor. This phenomenon, ascribed to the dissipationless exciton flow which dominates over the charge transport, is based on the much longer length scale of the change of the effective interface potential for electron scattering due to the coherence of the condensate than in the normal state.