Jan 18, 2016

「Subgap states in disordered superconductors with strong magnetic impurities」
Yakov V. Fominov 氏


講演題目: Subgap states in disordered superconductors with strong magnetic impurities
講 師 : Yakov V. Fominov 博士
     L. D. Landau Institute for Theoretical Physics
日 時 : 平成28年1月18日 (月) 16:30-18:00
場 所 : 北海道大学 工学部 物理工学系大会議室 (A1-17室)

要 旨 :
We study the density of states (DOS) in diffusive superconductors with point-like magnetic impurities of arbitrary strength described by the Poissonian statistics. The mean-field theory predicts a nontrivial structure of the DOS with the continuum of quasiparticle states and (possibly) the impurity band. In this approximation, all the spectral edges are hard, marking distinct boundaries between spectral regions of finite and zero DOS. Considering instantons in the replica sigma-model technique, we calculate the average DOS beyond the mean-field level and determine the smearing of the spectral edges due interplay of fluctuations of potential and non-potential disorder. The latter, represented by inhomogeneity in the concentration of magnetic impurities, affects the subgap DOS in two ways: via fluctuations of the pair-breaking strength and via induced fluctuations of the order parameter. In limiting cases, we reproduce previously reported results for the subgap DOS in disordered superconductors with strong magnetic impurities.

世話人  浅野 泰寛
北海道大学工学部応用理工系学科 (電話011-706-6115)

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