Thermal-assisted anisotropy and anisotropy-driven instability in the superfluid state of two-species fermionic polar molecules

We study the superfluid state of two-species heteronuclear Fermi gases with isotropic contact and anisotropic long-range dipolar interactions. We find that the temperature tends to increase the anisotropy of the pairing state, which is rather counterintuitive. We study the anisotropic properties of the system by examining the angular dependence of the number density distribution, the excitation spectrum and the pair correlation function. The competing effects of the contact interaction and the dipolar interaction upon the anisotropy are revealed. We derive and compute the superfluid mass density rho(ij) for the system. (C) 2012 Elsevier B.V. All rights reserved.