Proximity superconductivity in chiral kagome antiferromagnets

TL;DR

This paper models proximity-induced superconductivity in chiral kagome antiferromagnets, revealing a variety of topological phases and suggesting potential for spin-polarized superconductivity in spintronics applications.

Contribution

It introduces a minimal theoretical model that captures the phase diagram and topological transitions in proximity-induced superconductivity in kagome antiferromagnets.

Findings

Identification of valley-singlet superconducting phase consistent with experiments.

Discovery of topological superconducting phases with Chern numbers ±1, ±3.

Transition from superconducting to Chern insulator phases with varying canting.

Abstract

Recent experiments on the chiral kagome antiferromagnet Mn$_3$Ge have provided strong evidence of proximity-induced spin-polarized superconductivity. We introduce and explore a minimal model which exhibits a rich phase diagram as a function of chemical potential and spin canting. We find a valley-singlet superconducting phase for chemical potentials and canting consistent with the experimental system. This phase transitions into a Chern insulator at larger canting and gives way to topological superconducting phases with Chern numbers ${\cal C}_{\rm BdG} = \pm 1, \pm 3$ at other chemical potentials. Our results show that proximity-induced superconductivity in kagome antiferromagnets is a promising route towards exotic superconductivity with spin-polarized Cooper pairs, with potential applications in spintronics.