中国物理B ›› 2015, Vol. 24 ›› Issue (1): 17404-017404.doi: 10.1088/1674-1056/24/1/017404

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Variational Monte Carlo study of the nematic state in iron-pnictide superconductors with a five-orbital model

郑晓军a, 黄忠兵b c, 邹良剑a d   

  1. a Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, China;
    b Faculty of Physics and Electronic Technology, Hubei University, Wuhan 430062, China;
    c Beijing Computational Science Research Center, Beijing 100084, China;
    d Department of Physics, University of Science and Technology of China, Hefei 230026, China
  • 收稿日期:2014-11-05 修回日期:2014-11-10 出版日期:2015-01-05 发布日期:2015-01-05
  • 基金资助:

    Project supported by the National Natural Science Foundation of China (Grant Nos. 11274310, 11474287, 11174072, and 91221103) and the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20104208110001).

Variational Monte Carlo study of the nematic state in iron-pnictide superconductors with a five-orbital model

Zheng Xiao-Jun (郑晓军)a, Huang Zhong-Bing (黄忠兵)b c, Zou Liang-Jian (邹良剑)a d   

  1. a Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, China;
    b Faculty of Physics and Electronic Technology, Hubei University, Wuhan 430062, China;
    c Beijing Computational Science Research Center, Beijing 100084, China;
    d Department of Physics, University of Science and Technology of China, Hefei 230026, China
  • Received:2014-11-05 Revised:2014-11-10 Online:2015-01-05 Published:2015-01-05
  • Contact: Huang Zhong-Bing, Zou Liang-Jian E-mail:huangzb@hubu.edu.cn;zou@theory.issp.ac.cn
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Grant Nos. 11274310, 11474287, 11174072, and 91221103) and the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20104208110001).

摘要:

We perform a variational Monte Carlo study of the nematic state in iron-pnictide superconductors within a realistic five-orbital model. Our numerical results show that the nematic state, formed by introducing an anisotropic hopping order into the projected wave function, is not stable unless the off-site Coulomb interaction V exceeds a critical value. This demonstrates that V plays a key role in forming the nematic state in iron-pnictide superconductors. In the nematic state, the orbital order and the anisotropic spin correlations are consistent with the experimental observations. We argue that the experimentally observed anisotropic magnetic couplings and structural transition are associated with the nematic state and can be understood in a unified framework.

关键词: iron-pnictide superconductors, nematic state, off-site Coulomb interaction, variational Monte Carlo simulation

Abstract:

We perform a variational Monte Carlo study of the nematic state in iron-pnictide superconductors within a realistic five-orbital model. Our numerical results show that the nematic state, formed by introducing an anisotropic hopping order into the projected wave function, is not stable unless the off-site Coulomb interaction V exceeds a critical value. This demonstrates that V plays a key role in forming the nematic state in iron-pnictide superconductors. In the nematic state, the orbital order and the anisotropic spin correlations are consistent with the experimental observations. We argue that the experimentally observed anisotropic magnetic couplings and structural transition are associated with the nematic state and can be understood in a unified framework.

Key words: iron-pnictide superconductors, nematic state, off-site Coulomb interaction, variational Monte Carlo simulation

中图分类号:  (Pnictides and chalcogenides)

  • 74.70.Xa
71.10.Fd (Lattice fermion models (Hubbard model, etc.)) 74.25.Jb (Electronic structure (photoemission, etc.))