Topological Superconductivity in Two Dimensions with Mixed Chirality

TL;DR

This paper predicts a novel mixed chirality topological superconducting state in honeycomb materials, featuring counter-propagating edge states and a unique phase transition without bulk gap closing.

Contribution

It introduces a new mixed chirality $d$-wave superconducting state with topological properties in honeycomb systems, expanding understanding of topological phases.

Findings

Discovery of a mixed chirality $d$-wave state with topological edge states

Identification of a first-order phase transition without bulk gap closing

Prediction of counter-propagating edge states protected from intervalley scattering

Abstract

We find a mixed chirality $d$-wave superconducting state in the coexistence region between antiferromagnetism and interaction-driven superconductivity in lightly doped honeycomb materials. This state has a topological chiral $d+id$-wave symmetry in one Dirac valley but $d-id$-wave symmetry in the other valley and hosts two counter-propagating edge states, protected in the absence of intervalley scattering. A first-order topological phase transition, with no bulk gap closing, separates the chiral $d$-wave state at small magnetic moments from the mixed chirality $d$-wave phase.