Unconventional Fulde-Ferrell-Larkin-Ovchinnikov pairing states in a Fermi gas with spin-orbit coupling

TL;DR

This paper investigates the phase diagram and stability of unconventional FFLO pairing states in a 2D Fermi gas with synthetic spin-orbit coupling, revealing distinct nodal states and guiding future experimental detection.

Contribution

It provides a detailed characterization of FFLO states induced by spin-orbit coupling and Fermi surface asymmetry in a 2D Fermi gas, including topology and phase structure analysis.

Findings

Identification of several distinct nodal FFLO states

Detailed phase diagram with stability regions

Insights into density distributions in trapping potentials

Abstract

We study the phase diagram in a two-dimensional Fermi gas with the synthetic spin-orbit coupling that has recently been realized experimentally. In particular, we characterize in detail the properties and the stability region of the unconventional Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) states in such a system, which are induced by spin-orbit coupling and Fermi surface asymmetry. We identify several distinct nodal FFLO states by studying the topology of their respective gapless contours in momentum space. We then examine the phase structure and the number density distributions in a typical harmonic trapping potential under the local density approximation. Our studies provide detailed information on the FFLO pairing states with spin-orbit coupling and Fermi surface asymmetry, and will facilitate experimental detection of these interesting pairing states in the future.