Fulde-Ferrell superfluidity in ultracold Fermi gases with Rashba spin-orbit coupling

Abstract

We theoretically investigate the inhomogeneous Fulde-Ferrell (FF) superfluidity in a three dimensional atomic Fermi gas with Rashba spin-orbit coupling near a broad Feshbach resonance. We show that within mean-field theory the FF superfluid state is always more favorable than the standard Bardeen-Cooper-Schrieffer (BCS) superfluid state when an in-plane Zeeman field is applied. We present a qualitative finite-temperature phase diagram near resonance and argue that the predicted FF superfluid is observable with experimentally attainable temperatures (i.e., $T\sim0.2T_{F}$, where $T_{F}$ is the characteristic Fermi degenerate temperature).