Manifestation of chirality in the vortex lattice in a two-dimensional topological superconductor

TL;DR

This study investigates how chirality manifests in the vortex lattice of a two-dimensional topological superconductor, revealing the robustness of Majorana zero modes and the influence of spin-orbit coupling on vortex core properties.

Contribution

It demonstrates the manifestation of chirality in vortex structures and the robustness of Majorana zero modes against impurities in a 2D topological superconductor with Rashba spin-orbit coupling.

Findings

Chirality strongly influences vortex core structure at weak spin-orbit coupling.

Majorana zero modes are robust against nonmagnetic impurities.

Spin polarization of Majorana states depends on chirality and spin-orbit strength.

Abstract

We study the vortex lattice in a two-dimensional s-wave topological superconductor with Rashba spin-orbit coupling and Zeeman field by solving the Bogoliubov-de Gennes equations self-consistently for the superconducting order parameter. We find that when spin-orbit coupling is relatively weak, one of the two underlying chiralities in the topological superconducting state can be strongly manifest in the vortex core structure and govern the response of the system to vorticity and a nonmagnetic impurity where the vortex is pinned. The Majorana zero mode in the vortex core is found to be robust against the nonmagnetic impurity in that it remains effectively a zero-energy bound state regardless of the impurity potential strength and the major chirality. The spin polarization of the Majorana bound state depends on the major chirality for weak spin-orbit coupling, while it is determined simply by the vorticity when spin-orbit coupling is relatively strong.