Superconducting meron phase in locally noncentrosymmetric superconductors

TL;DR

This paper extends the theory of superconducting parity transitions by including vortex effects, predicting a novel meron lattice state in locally noncentrosymmetric superconductors and reproducing experimental phase diagrams.

Contribution

It introduces a Ginzburg-Landau framework incorporating vortex degrees of freedom to describe parity transitions and predicts a new meron lattice state in such superconductors.

Findings

Reproduces the H-T phase diagram of CeRh2As2.

Predicts a novel meron (half-skyrmion) lattice pseudospin texture.

Identifies parity transition from even to odd parity with increasing magnetic field.

Abstract

Theory of the superconducting parity transition is extended by incorporating the vortex degree of freedom. We employ the bilayer Rashba model representing locally noncentrosymmetric layered superconductors and derive the Ginzburg-Landau free energy functional. This formulation reveals the parity transition, where the even-parity superconducting state changes to the odd-parity one upon increasing the magnetic field under the vortex states. The H-T phase diagram of CeRh${}_{2}$As${}_{2}$ is quantitatively reproduced and a novel superconducting state with a meron (half-skyrmion) lattice pseudospin texture is predicted.