Odd-Parity Spin-Triplet Superconductivity in Centrosymmetric Antiferromagnetic Metals

TL;DR

This paper presents a theoretical route to realize odd-parity spin-triplet superconductivity in antiferromagnetic metals with inversion symmetry by breaking certain symmetries, leading to topologically nontrivial superconducting states.

Contribution

It introduces a mechanism to achieve odd-parity spin-triplet pairing in centrosymmetric antiferromagnets via symmetry breaking, predicting topological superconducting phases.

Findings

Spin-polarized Fermi surfaces enable spin-triplet pairing.

All resulting superconducting states are topologically nontrivial.

Layered double-perovskites are promising experimental candidates.

Abstract

We propose a route to achieve odd-parity spin-triplet superconductivity in metallic collinear antiferromagnets with inversion symmetry. Owing to the existence of hidden antiunitary symmetry, which we call the effective time-reversal symmetry (eTRS), the Fermi surfaces of ordinary antiferromagnetic metals are generally spin-degenerate, and spin-singlet pairing is favored. However, by introducing a local inversion symmetry breaking perturbation that also breaks the eTRS, we can lift the degeneracy to obtain spin-polarized Fermi surfaces. In the weak-coupling limit, the spin-polarized Fermi surfaces constrain the electrons to form spin-triplet Cooper pairs with odd-parity. Interestingly, all the odd-parity superconducting ground states we obtained host nontrivial band topologies manifested as chiral topological superconductors, second-order topological superconductors, and nodal superconductors. We propose that layered double-perovskites with collinear antiferromagnetism, sandwiched by conventional superconductors, are promising candidate systems where our theoretical ideas can be applied to.