Electrical and Thermal Transport in Antiferromagnet-Superconductor Junctions

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 the 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, voltage, and temperature bias. Furthermore, we show that the interplay between the Néel 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.