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arXiv · 2110.05288

Impurity-induced subgap states in superconductors with inhomogeneous pairing

A. A. Bespalov
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Abstract

We study subgap states induced by a single impurity in an s-wave superconductor with suppressed pairing. For concreteness, we consider a bulk superconductor containing a normal spherical region. We find that a point impurity in this system induces two Yu-Shiba-Rusinov states inside the minigap instead of one, which one would have in a homogeneous superconductor. Moreover, the subgap states appear even if the impurity is nonmagnetic. We prove that this result actually holds almost for any superconductor with a real and spatially inhomogeneous order parameter, if the quasiparticle spectrum is gapped.

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A. A. Bespalov. 2021-10-11. Impurity-induced subgap states in superconductors with inhomogeneous pairing. https://doi.org/10.1103/physrevb.100.094507

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