Topological superconductivity in Dirac semimetals

TL;DR

This paper develops a theoretical framework for understanding topological superconductivity in Dirac semimetals, highlighting how their unique electronic structure and topology can lead to symmetry-protected surface Majorana fermions, with potential applications to materials like Cd3As2.

Contribution

It introduces a novel theory linking Dirac points and surface Fermi loops to topological superconductivity in Dirac semimetals, emphasizing the role of orbital texture and structural transitions.

Findings

Topological superconductivity can be symmetry-protected in Dirac semimetals.

Surface Majorana fermions can emerge due to the nontrivial topology.

Application to Cd3As2 suggests real material relevance.

Abstract

Dirac semimetals host bulk band-touching Dirac points and a surface Fermi loop. We develop a theory of superconducting Dirac semimetals. Establishing a relation between the Dirac points and the surface Fermi loop, we clarify how the nontrivial topology of Dirac semimetals affects their superconducting state. We note that the unique orbital texture of Dirac points and a structural phase transition of the crystal favor symmetry-protected topological superconductivity with a quartet of surface Majorana fermions. We suggest possible application of our theory to recently discovered superconducting states in Cd$_3$As$_2$.