Interplay between Rashba spin-orbit coupling and adiabatic rotation in a two-dimensional Fermi gas

TL;DR

This paper investigates how Rashba spin-orbit coupling and adiabatic rotation influence the density profiles and superfluidity in a two-dimensional Fermi gas, revealing characteristic ring-shaped densities and phase separation phenomena.

Contribution

It provides a detailed analysis of the interplay between spin-orbit coupling and rotation effects on density profiles and superfluidity, including phase diagrams and critical rotation frequencies.

Findings

Rashba coupling induces ring-shaped density profiles at accessible temperatures.

Rapid rotation causes Landau level splitting, creating ziggurat-shaped density profiles.

Coriolis effects can break pairs and destroy superfluidity at specific rotation thresholds.

Abstract

We explore the trap profiles of a two-dimensional atomic Fermi gas in the presence of a Rashba spin-orbit coupling and under an adiabatic rotation. We first consider a non-interacting gas and show that the competition between the effects of Rashba coupling on the local density of single-particle states and the Coriolis effects caused by rotation gives rise to a characteristic ring-shaped density profile that survives at experimentally-accessible temperatures. Furthermore, Rashba splitting of the Landau levels takes the density profiles on a ziggurat shape in the rapid-rotation limit. We then consider an interacting gas under the BCS mean-field approximation for local pairing, and study the pair-breaking mechanism that is induced by the Coriolis effects on superfluidity, where we calculate the critical rotation frequencies both for the onset of pair breaking and for the complete destruction of superfluidity in the system. In particular, by comparing the results of fully-quantum-mechanical Bogoliubov-de Gennes approach with those of semi-classical local-density approximation, we construct extensive phase diagrams for a wide-range of parameter regimes in the trap where the aforementioned competition may, e.g., favor an outer normal edge that is completely phase separated from the central superfluid core by vacuum.