Vortex line in spin-orbit coupled atomic Fermi gases

TL;DR

This paper investigates vortex lines in spin-orbit coupled atomic Fermi gases, revealing how spin-orbit interactions influence bound states and particle currents, with implications for topological superfluid phases.

Contribution

It provides a detailed analysis of vortex core and edge states in Rashba spin-orbit coupled Fermi gases using Bogoliubov-de Gennes formalism, highlighting spin component counterflow effects.

Findings

Core- and edge-bound states are detectable via local density of states.

Pseudo-spin components exhibit counterflow near the cylinder edge.

Counterflow strength increases with spin-orbit coupling.

Abstract

It has recently been shown that the spin-orbit coupling gives rise to topologically-nontrivial and thermodynamically-stable gapless superfluid phases when the pseudo-spin populations of an atomic Fermi gas is imbalanced, with the possibility of featuring Majorana zero-energy quasiparticles. In this paper, we consider a Rashba-type spin-orbit coupling, and use the Bogoliubov-de Gennes formalism to analyze a single vortex line along a finite cylinder with a periodic boundary condition. We show that the signatures for the appearance of core- and edge-bound states can be directly found in the density of single-particle states and particle-current density. In particular, we find that the pseudo-spin components counterflow near the edge of the cylinder, the strength of which increases with increasing spin-orbit coupling.