Three-dimensional time reversal invariant topological superconductivity in doped chiral topological semimetals

TL;DR

This paper proposes that doped chiral topological semimetals can host three-dimensional time reversal invariant topological superconductivity, featuring surface Majorana fermions, influenced by their nontrivial band topology and phonon-mediated interactions.

Contribution

It identifies doped chiral topological semimetals as new candidates for topological superconductivity and elucidates the role of their nontrivial topology in supporting Majorana surface states.

Findings

Existence of topological superconductivity in doped chiral topological semimetals.

Surface Majorana fermions are predicted in these materials.

Electron-electron interactions mediated by phonons favor topological superconductivity.

Abstract

Chiral topological semimetals host multifold degenerate band crossing points under the protection of crystalline symmetries. In this paper, we suggest that the recently discovered chiral topological semimetals in space group 198, parts of which are superconducting upon doping, can be new candidates of time reversal invariant topological superconductors. By investigating the Fermi surfaces around the band crossing points that carry nonzero Chern numbers, we clarify how the nontrivial topology of chiral topological semimetals affects their superconducting state and show the existence of topological superconductivity in $s_\pm$-wave pairing with surface Majorana fermions. We further demonstrate that the topological superconductivity is favored by the inter-unit-cell phonon-mediated electron-electron interaction.