1211.5780 (Fan Wu et al.)

Unconventional superfluid in a two-dimensional Fermi gas with
anisotropic spin-orbit coupling and Zeeman fields    [PDF]

Fan Wu, Guang-Can Guo, Wei Zhang, Wei Yi

We study the phase diagram of a two-dimensional ultracold Fermi gas with the synthetic spin-orbit coupling (SOC) that has recently been realized at NIST. Due to the coexistence of SOC and effective Zeeman fields in the NIST scheme, the system shows rich structure of spatial phase separation involving exotic gapless superfluid and the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state. In particular, we characterize the stability region of the FFLO state and demonstrate its unique features under SOC. We also show that an effective transverse Zeeman field can qualitatively change the landscape of the thermodynamic potential, and eradicate the pairing instability in the large polarization limit typical of a Fermi gas with SOC. These interesting features may be probed for example by measuring the {\it in-situ} density profiles or by the momentum-resolved rf spectroscopy.

View original: http://arxiv.org/abs/1211.5780