Odd–Parity Spin–Triplet Superconductivity in Antiferromagnetic Metals Lacking Effective Time-Reversal Symmetries*

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 symmetries, which we call the effective time-reversal symmetries (eTRS), the Fermi surfaces of such systems are generally spin-degenerate. 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. Furthermore, we find that the odd-parity superconducting states host nontrivial band topology. We also solve the finite-size tight-binding models to show the boundary modes appear as a consequence of the bulk topology.