Zeeman field induced topological phase transitions in triplet superconductors

TL;DR

This paper develops a Ginzburg-Landau framework to analyze how Zeeman fields influence topological phase transitions in triplet superconductors, revealing the potential for inducing nontrivial topological phases with edge modes.

Contribution

It introduces a comprehensive Ginzburg-Landau theory for triplet superconductors under Zeeman fields, connecting microscopic models to topological phase transitions and edge phenomena.

Findings

Zeeman field can induce topological phase transitions near critical chemical potential.

Certain Zeeman field directions lead to nodal phases with Majorana flat bands.

The theory is supported by a microscopic mean-field analysis of the doped Kitaev-Heisenberg model.

Abstract

We develop a general Ginzburg-Landau theory which describes the effect of a Zeeman field on the superconducting order parameter in triplet superconductors. Starting from Ginzburg-Landau theories that describe fully gapped time-reversal symmetric triplet superconductors, we show that the Zeeman field has dramatic effects on the topological properties of the superconductors. In particular, in the vicinity of a critical chemical potential separating two topologically distinct phases, it is possible to induce a phase transition to a topologically nontrivial phase which supports chiral edge modes. Moreover, for specific directions of the Zeeman field, we obtain nodal superconducting phases with an emerging chiral symmetry, and with Majorana flat bands at the edge. The Ginzburg-Landau theory is microscopically supported by a self-consistent mean-field theory of the doped Kitaev-Heisenberg model.