Fulde-Ferrell-Like Molecular States in Spin-Orbit Coupled Ultracold Fermi Gases

We study the molecular state in three-component Fermi gases with a single impurity of ⁶ Li immersing in a no-interacting Fermi sea of ⁴⁰ K in the presence of an equal weight combination of Rashba-type and Dresselhaus-type spin-orbit coupling. In the region where the Fermi sea has two disjointed Fermi surfaces, we find that there are two Fulde–Ferrell-like molecular states with dominating contributions from the lower helicity branch. Decreasing the scattering length or the spin-orbit coupled Fermi energy, we find the Fulde–Ferrell-like molecular state with small center-of-mass momentum is always energy favored and the other one will suddenly disappear. (paper)