中国物理B ›› 2015, Vol. 24 ›› Issue (5): 50502-050502.doi: 10.1088/1674-1056/24/5/050502

所属专题: TOPICAL REVIEW — Precision measurement and cold matters

• TOPICAL REVIEW—Precision measurement and cold matters • 上一篇    下一篇

Three-dimensional spin–orbit coupled Fermi gases: Fulde–Ferrell pairing, Majorana fermions, Weyl fermions, and gapless topological superfluidity

Xia-Ji Liua, Hui Hua, Han Pub c   

  1. a Center for Quantum and Optical Science, Swinburne University of Technology, Melbourne 3122, Australia;
    b Department of Physics and Astronomy, and Rice Quantum Institute, Rice University, Houston, TX 77251, USA;
    c Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China
  • 收稿日期:2014-11-14 修回日期:2014-12-02 出版日期:2015-05-05 发布日期:2015-05-05
  • 基金资助:
    Project supported by the ARC Discovery Projects (Grant Nos. FT140100003, FT130100815, DP140103231, and DP140100637), the National Basic Research Program of China (Grant No. 2011CB921502), the US National Science Foundation, and the Welch Foundation (Grant No. C-1669).

Three-dimensional spin–orbit coupled Fermi gases: Fulde–Ferrell pairing, Majorana fermions, Weyl fermions, and gapless topological superfluidity

Xia-Ji Liua, Hui Hua, Han Pub c   

  1. a Center for Quantum and Optical Science, Swinburne University of Technology, Melbourne 3122, Australia;
    b Department of Physics and Astronomy, and Rice Quantum Institute, Rice University, Houston, TX 77251, USA;
    c Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China
  • Received:2014-11-14 Revised:2014-12-02 Online:2015-05-05 Published:2015-05-05
  • Contact: Han Pu E-mail:hpu@rice.edu
  • About author:05.30.Fk; 03.75.Hh; 03.75.Ss; 67.85.-d
  • Supported by:
    Project supported by the ARC Discovery Projects (Grant Nos. FT140100003, FT130100815, DP140103231, and DP140100637), the National Basic Research Program of China (Grant No. 2011CB921502), the US National Science Foundation, and the Welch Foundation (Grant No. C-1669).

摘要: We theoretically investigate a three-dimensional Fermi gas with Rashba spin–orbit coupling in the presence of both out-of-plane and in-plane Zeeman fields. We show that, driven by a sufficiently large Zeeman field, either out-of-plane or in-plane, the superfluid phase of this system exhibits a number of interesting features, including inhomogeneous Fulde–Ferrell pairing, gapped or gapless topological order, and exotic quasi-particle excitations known as Weyl fermions that have linear energy dispersions in momentum space (i.e., massless Dirac fermions). The topological superfluid phase can have either four or two topologically protected Weyl nodes. We present the phase diagrams at both zero and finite temperatures and discuss the possibility of their observation in an atomic Fermi gas with synthetic spin–orbit coupling. In this context, topological superfluid phase with an imperfect Rashba spin–orbit coupling is also studied.

关键词: Fulde–, Ferrell superfluid, topological superfluid, spin–, orbit coupling

Abstract: We theoretically investigate a three-dimensional Fermi gas with Rashba spin–orbit coupling in the presence of both out-of-plane and in-plane Zeeman fields. We show that, driven by a sufficiently large Zeeman field, either out-of-plane or in-plane, the superfluid phase of this system exhibits a number of interesting features, including inhomogeneous Fulde–Ferrell pairing, gapped or gapless topological order, and exotic quasi-particle excitations known as Weyl fermions that have linear energy dispersions in momentum space (i.e., massless Dirac fermions). The topological superfluid phase can have either four or two topologically protected Weyl nodes. We present the phase diagrams at both zero and finite temperatures and discuss the possibility of their observation in an atomic Fermi gas with synthetic spin–orbit coupling. In this context, topological superfluid phase with an imperfect Rashba spin–orbit coupling is also studied.

Key words: Fulde–, Ferrell superfluid, topological superfluid, spin–, orbit coupling

中图分类号:  (Fermion systems and electron gas)

  • 05.30.Fk
03.75.Hh (Static properties of condensates; thermodynamical, statistical, and structural properties) 03.75.Ss (Degenerate Fermi gases) 67.85.-d (Ultracold gases, trapped gases)