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

Abstract

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 anisotropic SOC and effective Zeeman fields in the NIST scheme, the system shows rich structure of phase separation involving exotic gapless superfluid and Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) pairing states with different center-of-mass momentum. In particular, we characterize the stability region of FFLO states and demonstrate their unique features under SOC. We then show that the effective transverse Zeeman field in the NIST scheme can qualitatively change the landscape of the thermodynamic potential which leads to intriguing effects such as the disappearance of pairing instability, the competition between different FFLO states, and the stabilization of a fully gapped FFLO state. These interesting features may be probed for example by measuring the in-situ density profiles or by the momentum-resolved radio-frequency spectroscopy.

7 pages, 6 figures. with updated figures and discussions

References in corpus (12)

• Spin-Injection Spectroscopy of a Spin-Orbit Coupled Fermi Gas
• Non-Abelian Topological Order in S-Wave Superfluids of Ultracold Fermionic Atoms
• Using photoemission spectroscopy to probe a strongly interacting Fermi gas
• $p_x+i{p}_y$ superfluid from s-wave interactions of fermionic cold atoms
• Radiofrequency spectroscopy of a strongly interacting two-dimensional Fermi gas
• Observation of a two-dimensional Fermi gas of atoms
• Effect of Induced Spin-Orbit Coupling for Atoms via Laser Fields
• BCS-BEC crossover induced by a synthetic non-Abelian gauge field
• Crossover from 2D to 3D in a weakly interacting Fermi gas
• Topologically non-trivial superconductivity in spin-orbit coupled systems: Bulk phases and quantum phase transitions
• Superfluidity at the BEC-BCS crossover in two-dimensional Fermi gases with population and mass imbalance
• Molecule and polaron in a highly polarized two-dimensional Fermi gas with spin-orbit coupling

Cited by in corpus (1)

• Finite-Momentum Dimer Bound State in Spin-Orbit Coupled Fermi Gas