BCS-BEC Crossover and Topological Phase Transition in 3D Spin-Orbit Coupled Degenerate Fermi Gases

ORAL

Abstract

We investigate the BCS-BEC crossover in three-dimensional degenerate Fermi gases in the presence of spin-orbit coupling (SOC) and Zeeman field. We show that the superfluid order parameter destroyed by a large Zeeman field can be restored by the SOC. With increasing strengths of the Zeeman field, there is a series of topological quantum phase transitions from a nontopological superfluid state with fully gapped fermionic spectrum to a topological superfluid state with four topologically protected Fermi points (i.e., nodes in the quasiparticle excitation gap) and then to a second topological superfluid state with only two Fermi points. The quasiparticle excitations near the Fermi points realize the long-sought low-temperature analog of Weyl fermions of particle physics. We show that the topological phase transitions can be probed using the experimentally realized momentum-resolved photoemission spectroscopy. Phys. Rev. Lett. 107, 195303 (2011).

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Authors

  • Ming Gong

    • Washington State University
    • Department of Physics and Astronomy, Washington State University, Pullman, Washington, 99164, USA

  • Sumanta Tewari

    • Department of Physics and Astronomy, Clemson University, Clemson, South Carolina 29634, USA

  • Chuanwei Zhang

    • Department of Physics and Astronomy, Washington State University, Pullman, WA
    • Department of Physics and Astronomy, Washington State University, Pullman, WA 99164
    • Washington State University
    • Department of Physics and Astronomy, Washington State University, Pullman, Washington, 99164, USA