Electrical and Thermal Transport in Antiferromagnet-Superconductor Junctions

TL;DR

This paper explores unique electrical and thermal transport phenomena in antiferromagnet-superconductor junctions, revealing new scattering processes and anisotropic effects that differ from traditional metal and ferromagnet interfaces.

Contribution

It introduces the presence of two new scattering processes in AF-S junctions and analyzes their impact on transport properties using the BTK formalism.

Findings

Transport properties differ qualitatively from N--S and F--S junctions.

Electrical and thermal conductance depend on antiferromagnetic exchange strength.

Large anisotropic magnetoresistance arises from Nél vector and spin-orbit coupling.

Abstract

We demonstrate that antiferromagnet-superconductor (AF-S) junctions show qualitatively different transport properties than normal metal-superconductor (N--S) and ferromagnet-superconductor (F-S) junctions. We attribute these transport features to presence of two new scattering processes in AF--S junctions, i.e., specular reflection of holes and retroreflection of electrons. Using the Blonder-Tinkham-Klapwijk formalism, we find that the electrical and thermal conductance depend nontrivially on antiferromagnetic exchange strength. Furthermore, we show that the interplay between the N\'eel vector direction and the interfacial Rashba spin-orbit coupling leads to a large anisotropic magnetoresistance. The unusual transport properties make AF--S interfaces unique among the traditional condensed-matter-system-based superconducting junctions.