中国物理B ›› 2025, Vol. 34 ›› Issue (5): 57401-057401.doi: 10.1088/1674-1056/adbbbe

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Anisotropic two-band α-model and its application to layered chalcogenide superconductor NbSe2

Jiang-Ning Zhang(张江宁)1, Guo Wang(王果)2, Tian-Yi Han(韩天意)2, and Hai Huang(黄海)1,†   

  1. 1 Department of Mathematics and Physics, North China Electric Power University, Beijing 102206, China;
    2 School of Nuclear Science and Engineering, North China Electric Power University, Beijing 102206, China
  • 收稿日期:2024-12-16 修回日期:2025-02-28 接受日期:2025-03-03 出版日期:2025-04-18 发布日期:2025-04-28
  • 通讯作者: Hai Huang E-mail:huanghai@ncepu.edu.cn

Anisotropic two-band α-model and its application to layered chalcogenide superconductor NbSe2

Jiang-Ning Zhang(张江宁)1, Guo Wang(王果)2, Tian-Yi Han(韩天意)2, and Hai Huang(黄海)1,†   

  1. 1 Department of Mathematics and Physics, North China Electric Power University, Beijing 102206, China;
    2 School of Nuclear Science and Engineering, North China Electric Power University, Beijing 102206, China
  • Received:2024-12-16 Revised:2025-02-28 Accepted:2025-03-03 Online:2025-04-18 Published:2025-04-28
  • Contact: Hai Huang E-mail:huanghai@ncepu.edu.cn

摘要: The generalized $\alpha$-model for anisotropic two-band superconductivity is consistently constructed with the consideration of weak interband electron-electron interaction. Tailored from the two-band BCS theory, the developed framework can be applied to investigate thermodynamic properties of intraband strong-coupling superconductors. Accordingly, we perform a calculation on the temperature dependence of specific heat and obtain an analytic expression for specific heat jump at the superconducting critical temperature. Meanwhile, we also compute the superfluid density and the spin susceptibility with this formalism. Given the low-temperature superconducting gaps from experimental measurement, all of our theoretical results can fit the experimental data of the layered two-band superconductor NbSe$_2$ well.

关键词: two-band superconductivity, anisotropic $\alpha$-model, specific heat, NbSe$_2$

Abstract: The generalized $\alpha$-model for anisotropic two-band superconductivity is consistently constructed with the consideration of weak interband electron-electron interaction. Tailored from the two-band BCS theory, the developed framework can be applied to investigate thermodynamic properties of intraband strong-coupling superconductors. Accordingly, we perform a calculation on the temperature dependence of specific heat and obtain an analytic expression for specific heat jump at the superconducting critical temperature. Meanwhile, we also compute the superfluid density and the spin susceptibility with this formalism. Given the low-temperature superconducting gaps from experimental measurement, all of our theoretical results can fit the experimental data of the layered two-band superconductor NbSe$_2$ well.

Key words: two-band superconductivity, anisotropic $\alpha$-model, specific heat, NbSe$_2$

中图分类号:  (Theories and models of superconducting state)

  • 74.20.-z
74.20.Fg (BCS theory and its development) 74.25.Bt (Thermodynamic properties)