Tail states in clean superconductors with magnetic impurities.
We analyze the behavior of the density of states in a singlet s-wave superconductor with weak magnetic impurities in the clean limit. By using the method of optimal fluctuation and treating the order parameter self-consistently we show that the density of states is finite everywhere in the superconducting gap, and that it varies as ln(N(E) proportional to -/E-Delta(0)/((7-d)/4) near the mean field gap edge Delta(0) in a d-dimensional superconductor. In contrast to most studied cases the optimal fluctuation is strongly anisotropic.
Shytov
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AV
Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106, USA.
Vekhter
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I
Gruzberg
I A
IA
Balatsky
A V
AV