Vortex states and Majorana fermions in spin-orbit coupled semiconductor-superconductor hybrid structures

TL;DR

This paper investigates vortex states and Majorana fermions in a spin-orbit coupled semiconductor-superconductor hybrid, revealing topological phases, vortex core structures, and spectral asymmetries through self-consistent microscopic calculations.

Contribution

It provides a detailed analysis of vortex core energy spectra and confirms the existence of Majorana fermions in a specific topological phase using a microscopic approach.

Findings

Majorana fermions exist in the non-trivial topological phase.

Two distinct trivial phases differ by vortex core structure.

Energy spectrum asymmetry relates to Zeeman splitting and vortex rotation.

Abstract

We study the energy spectrum of a vortex core in a two-dimensional semiconductor with Rashba spin-orbit interaction and proximity-coupled to a conventional superconductor and a ferromagnetic insulator. We perform self-consistent calculations using the microscopic tight-binding Bogoliubov-de Gennes method on a lattice and confirm the existence of Majorana fermions in the non-trivial topological phase. We also find two different topologically trivial bulk superconducting phases, only differing in the type of vortex core structure they support and separated by a zero-energy excitation. Furthermore, we find an asymmetry in the energy spectrum with respect to both Zeeman splitting and vortex rotation direction and explain its physical origin.