Influence of Fermi surface topology on the quasiparticle spectrum in the vortex state

Abstract

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, that has been used frequently in analysis of tunneling data. We suggest a new 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 MgB${}_2$ 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.

arXiv comment12 pages 12 figures

References in corpus (9)

• Superconductivity of metallic boron in MgB_2
• Beyond Eliashberg superconductivity in MgB2: anharmonicity, two-phonon scattering, and multiple gaps
• Vortex Imaging in the pi-Band of Magnesium Diboride
• Superconducting Gap Structure of Spin-Triplet Superconductor Sr_2RuO_4 Studied by Thermal Conductivity
• Observation of d-wave scaling relations in the mixed-state specific heat of YBa2Cu3O7
• Fermi surface topology and the upper critical field in two-band superconductors - application to MgB2
• Ansiotropic s- wave superconductivity in borocarbides LuNi2B2C and YNi2B2C
• Spectrum of low energy excitations in the vortex state: comparison of Doppler shift method to quasiclassical approach
• Anomalous microwave conductivity coherence peak in c-axis MgB2 thin film

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• Electronic state around vortex in a two-band superconductor
• Magnetic-Field Dependences of Thermodynamic Quantities in the Vortex State of Type-II Superconductors
• Effects of Fermi surface and superconducting gap structure in the field-rotational experiments: A possible explanation of the cusp-like singularity in YNi${}_2$B${}_2$C
• Induced Kramer-Pesch-Effect in a Two Gap Superconductor: Application to MgB2
• Damping of the de Haas-van Alphen oscillations in the superconducting state of MgB_2
• de Haas-van Alphen effect investigations of the electronic structure of pure and aluminum-doped MgB_2
• Transfer-matrix approach to multiband Josephson junctions
• Fermi surface topology and vortex state in MgB2
• Thermal conductivity in the vortex state of the superconductor UPd_2Al_3
• Basal-Plane Magnetic Anisotropies of High-kappa d-Wave Superconductors in a Mixed State: A Quasiclassical Approach
• Superconductivity of Magnesium Diboride: Theoretical Aspects
• Effect of uniaxially anisotropic Fermi surface on the quasiparticle scattering inside a vortex core in unconventional superconductors
• Quasiclassical Theory for Thermodynamic Properties of the Two-Band Superconductor MgB${}_2$ under Magnetic Fields
• Quasiclassical theory of vortex states in locally non-centrosymmetric superconductors: application to CeRh${}_2$As${}_2$