Interplay of Rashba and Dresselhaus Spin-Orbit Couplings on the Stability of Topological FFLO Phases in 1D Fermi Gases

TL;DR

This paper explores how Rashba and Dresselhaus spin-orbit couplings influence the stability of topological FFLO phases in 1D Fermi gases, revealing that Dresselhaus coupling uniquely stabilizes intraband FFLO superfluidity.

Contribution

It demonstrates the distinct role of Dresselhaus spin-orbit coupling in stabilizing intraband FFLO phases, advancing understanding of topological superfluids in spin-orbit coupled systems.

Findings

Dresselhaus SOC stabilizes intraband FFLO phases.

Rashba SOC stabilizes zero-momentum pairing.

Enhanced spin polarization promotes topological superfluidity.

Abstract

We investigate the stabilization of topological Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phases, with a specific emphasis on the intraband FFLO phase, in a one-dimensional (1D) Fermi gas subjected to an external magnetic field. This research highlights the crucial role of the interplay between Rashba spin-orbit coupling (RSOC) and Dresselhaus spin-orbit coupling (DSOC). Employing a Fermi-Hubbard model alongside the density matrix renormalization group (DMRG) method, we examine the combined effects of RSOC and DSOC on these exotic superfluid phases, taking into account attractive fermionic interactions. Our principal finding reveals that while RSOC primarily stabilizes conventional zero-momentum pairing, DSOC performs a distinct and crucial role in selectively stabilizing the intraband FFLO phase. This stabilization is achieved by enhancing spin polarization within a single helicity band and suppressing interband coherence, thereby facilitating the formation of finite-momentum FFLO pairs within the same band and resulting in the emergence of a topologically nontrivial superfluid. This targeted control of intraband FFLO pairing paves the way for new strategies in the manipulation of superfluid phases in spin-orbit coupled systems and offers essential insights for experimental realizations in ultracold atomic gases, with implications for topological quantum computing and Majorana fermions.