$d+id$ chiral superconductivity in a triangular lattice from trigonal bipyramidal complexes

TL;DR

This paper predicts that trigonal bipyramidal complex-based triangular lattice materials can host chiral $d+id$ superconductivity with topological properties, including Majorana modes, driven by electron interactions.

Contribution

It introduces a three-orbital model for these materials and demonstrates the emergence of chiral $d+id$ pairing as the dominant superconducting state.

Findings

Chiral $d+id$ superconductivity is the leading pairing symmetry.

The state has a nontrivial topological Chern number.

Majorana zero modes can exist in vortex cores.

Abstract

We model the newly predicted high-$T_c$ superconducting candidates constructed by corner-shared trigonal bipyramidal complexes with an effective three-orbital tight-banding Hamiltonian and investigate the pairing symmetry of their superconducting states driven by electron-electron interactions. Our combined weak and strong coupling based calculations consistently identify the chiral $d+id$ superconductivity as the leading pairing symmetry in a wide doping range with realistic interaction parameters. This pairing state has nontrivial topological Chern-number and can host gapless chiral edge modes, and the vortex cores under magnetic field can carry Majorana zero modes.