Nodal S-wave Superconductivity in Antiferromagnetic Semimetals

TL;DR

This paper explores how s-wave spin-singlet pairing induces a variety of topological and gap structures in antiferromagnetic semimetals, revealing a new form of nodal superconductivity driven by Dirac fermions.

Contribution

It provides a general criterion for predicting topological transitions between gapped and nodal superconducting phases in antiferromagnetic semimetals.

Findings

Identification of symmetry-driven topological transitions

Demonstration of microscopic mechanisms controlling quasiparticle spectra

Unveiling a novel type of nodal superconductivity from Dirac fermions

Abstract

We investigate the impact of s-wave spin-singlet pairing on antiferromagnetic semimetals with Dirac points or nodal loops at the Fermi level. The electron pairing is generally shown to convert the semimetal into a tunable nodal superconductor. The changeover from fully gapped to gapless phases is dictated by symmetry properties of the antiferromagnetic-superconducting state that set the occurrence of a large variety of electronic topological transitions. We provide a general criterion for predicting a series of transitions between nodal and fully gapped superconducting phases. Different types of antiferromagnetic patterns are then employed to explicitly demonstrate the microscopic mechanisms that control the character of the quasiparticle spectrum. These findings unveil a novel type of nodal superconductivity emerging from the interplay of Dirac fermions and conventional forms of ordering.