Robust realization of spin-polarized specular Andreev reflection in V$_2$O-based altermagnets

TL;DR

This paper theoretically demonstrates robust spin-polarized specular Andreev reflection in V$_2$O-based altermagnets and proposes a setup for its experimental detection, highlighting potential for spin-resolved Cooper pair splitting.

Contribution

It introduces a microscopic model of V$_2$O-based altermagnets and shows their capability to produce spin-polarized Andreev reflection with a proposed detection method.

Findings

Robust spin-polarized specular Andreev reflection observed in the model.

Proposed multiterminal setup for nonlocal conductance detection.

V$_2$O-based altermagnets as platforms for spin-resolved Cooper pair splitting.

Abstract

We theoretically investigate charge transport in a junction between a conventional superconductor and a V$_2$O-based altermagnet exhibiting distinctive spin-split quasi-one-dimensional Fermi surfaces. The altermagnet is described by a microscopically motivated six-orbital model that incorporates sublattice degrees of freedom associated with both V and O sites. Based on calculations performed under various boundary conditions, we demonstrate the robust emergence of specular Andreev reflection with a distinctive spin polarization. Furthermore, we propose an efficient multiterminal setup to detect this specular Andreev reflection through nonlocal conductance measurements. Our results establish V$_2$O-based altermagnets as a promising platform for realizing spin-resolved Cooper pair splitting, which is essential for generating energy-entangled electron pairs.