2003/09/05 by S. Graser, S. Gräser, T. Dahm +1 · 3 citations
Materials Science · Physics and Astronomy · #Iron-based superconductors research #Physics of Superconductivity and Magnetism #Superconductivity in MgB2 and Alloys #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.69.014511
published as Phys.Rev. B69 (2004) 014511 · 12 pages 12 figures
arxiv created 2003/09/05 · openalex publication_date 2004/01/23 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study the influence of Fermi surface topology on the quasiparticle density of states in the vortex state of type-II superconductors. We observe that the field dependence and the shape of the momentum and spatially averaged density of states is affected significantly by the topology of the Fermi surface. We show that this behavior can be understood in terms of characteristic Fermi surface functions and that an important role is played by the number of points on the Fermi surface at which the Fermi velocity is directed parallel to the magnetic field. A critical comparison is made with a broadened BCS-type density of states, which has been used frequently in analysis of tunneling data. We suggest a formula as a replacement for the broadened BCS model for the special case of a cylindrical Fermi surface. We apply our results to the two-gap superconductor MgB2 and show that in this particular case the field dependence of the partial densities of states of the two gaps behaves very differently due to the different topologies of the corresponding Fermi surfaces, in qualitative agreement with recent tunneling experiments.