中国物理B ›› 2015, Vol. 24 ›› Issue (3): 30305-030305.doi: 10.1088/1674-1056/24/3/030305

• GENERAL • 上一篇    下一篇

Topological phase transitions driven by next-nearest-neighbor hopping in noncentrosymmetric cold Fermi gases

王瑞a b, 张存喜a, 计青山a   

  1. a Department of Electronic Information Science and Engineering, Zhejiang Ocean University, Zhoushan 316022, China;
    b National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China
  • 收稿日期:2014-06-29 修回日期:2014-10-11 出版日期:2015-03-05 发布日期:2015-03-05
  • 基金资助:

    Project supported by the National Natural Science Foundation of China (Grant No. 11304281) and the Natural Science Foundation of Zhejiang Province, China (Grant No. LY13D060002).

Topological phase transitions driven by next-nearest-neighbor hopping in noncentrosymmetric cold Fermi gases

Wang Rui (王瑞)a b, Zhang Cun-Xi (张存喜)a, Ji Qing-Shan (计青山)a   

  1. a Department of Electronic Information Science and Engineering, Zhejiang Ocean University, Zhoushan 316022, China;
    b National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China
  • Received:2014-06-29 Revised:2014-10-11 Online:2015-03-05 Published:2015-03-05
  • Contact: Wang Rui E-mail:wangrui@zjou.edu.cn
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Grant No. 11304281) and the Natural Science Foundation of Zhejiang Province, China (Grant No. LY13D060002).

摘要:

We investigate the topological phase marked by the Thouless-Kohmoto-Nightingale-Nijs (TKNN) number and the phase transitions driven by the next nearest neighbor (NNN) hopping in noncentrosymmetric cold Fermi gases, both spin-singlet pairing and spin-triplet pairing are considered. There exists a critical t'c for the NNN hopping, at which the quantum phase transition occurs, and the system changes from an Abelian (non-Abelian) phase to a non-Abelian (Abelian) one. By numerically diagonalizing the Hamiltonian in the real space, the energy spectra with edge states for different topological phases and the Majorana zero modes are discussed. Although the spin-triplet pairing does not contribute to the gap closing and the phase diagram, it induces gapless states in the presence of a magnetic field, and the TKNN number in this region is still zero.

关键词: topological phase transition, Fermi gases, Majorana fermion

Abstract:

We investigate the topological phase marked by the Thouless-Kohmoto-Nightingale-Nijs (TKNN) number and the phase transitions driven by the next nearest neighbor (NNN) hopping in noncentrosymmetric cold Fermi gases, both spin-singlet pairing and spin-triplet pairing are considered. There exists a critical t'c for the NNN hopping, at which the quantum phase transition occurs, and the system changes from an Abelian (non-Abelian) phase to a non-Abelian (Abelian) one. By numerically diagonalizing the Hamiltonian in the real space, the energy spectra with edge states for different topological phases and the Majorana zero modes are discussed. Although the spin-triplet pairing does not contribute to the gap closing and the phase diagram, it induces gapless states in the presence of a magnetic field, and the TKNN number in this region is still zero.

Key words: topological phase transition, Fermi gases, Majorana fermion

中图分类号:  (Phases: geometric; dynamic or topological)

  • 03.65.Vf
05.30.Rt (Quantum phase transitions) 67.85.Lm (Degenerate Fermi gases) 05.30.Fk (Fermion systems and electron gas)