Ab Initio Calculations of H_<c2> for Nb, NbSe_2, and MgB_2

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Author(s)

Abstract

We report on the quantitative calculations of the upper critical field H_<c2> for clean type-II superconductors Nb, NbSe_2, and MgB_2 within the weak-coupling theory. The Fermi surface anisotropy is fully taken into account by the energy band data from ab initio electronic structure calculations. The results for Nb and NbSe_2 excellently reproduce both temperature and directional dependences of measured H_<c2> curves without any adjustable parameters, including a marked upward curvature of NbSe_2 near T_c. As for MgB_2, a good fit is obtained for a π/σ gap ratio of 〜0.3, which is close to that from a first-principles strong-coupling theory [H. J. Choi et al : Nature 418 (2002) 758]. Our results indicate the importance of Fermi surface anisotropy in describing H_<c2>.

Journal

  • Journal of the Physical Society of Japan

    Journal of the Physical Society of Japan 73(11), 2924-2927, 2004-11-15

    The Physical Society of Japan (JPS)

References:  37

Codes

  • NII Article ID (NAID)
    110001979231
  • NII NACSIS-CAT ID (NCID)
    AA00704814
  • Text Lang
    ENG
  • Article Type
    SHO
  • ISSN
    00319015
  • NDL Article ID
    7156546
  • NDL Source Classification
    ZM35(科学技術--物理学)
  • NDL Call No.
    Z53-A404
  • Data Source
    CJP  NDL  NII-ELS 
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