Print Email Facebook Twitter Density of states in gapped superconductors with pairing-potential impurities Title Density of states in gapped superconductors with pairing-potential impurities Author Bespalov, Anton (Russian Academy of Sciences; Université Grenoble Alpes) Houzet, Manuel (Université Grenoble Alpes) Meyer, Julia S. (Université Grenoble Alpes) Nazarov, Y.V. (TU Delft QN/Nazarov Group) Date 2016-03-21 Abstract We study the density of states in disordered s-wave superconductors with a small gap anisotropy. We consider disorder in the form of common nonmagnetic scatterers and pairing-potential impurities, which interact with electrons via an electric potential and a local distortion of the superconducting gap. Using quasiclassical Green functions, we determine the bound-state spectrum at a single impurity and the density of states at a finite concentration of impurities. We show that, if the gap is isotropic, an isolated impurity with suppressed pairing supports an infinite number of Andreev states. With growing impurity concentration, the energy-dependent density of states evolves from a sharp gap edge with an impurity band below it to a smeared BCS singularity in the so-called universal limit. Within one spin sector, pairing-potential impurities and weak spin-polarized magnetic impurities have essentially the same effect on the density of states. We note that, if a gap anisotropy is present, the density of states becomes sensitive to ordinary potential disorder, and the existence of Andreev states localized at pairing-potential impurities requires special conditions. An unusual feature related to the anisotropy is a nonmonotonic dependence of the gap edge smearing on impurity concentration. To reference this document use: http://resolver.tudelft.nl/uuid:8cea7557-81b3-43d0-a77f-1a44c4ce60d5 DOI https://doi.org/10.1103/PhysRevB.93.104521 ISSN 1098-0121 Source Physical Review B (Condensed Matter and Materials Physics), 93 (10), 1-17 Part of collection Institutional Repository Document type journal article Rights © 2016 Anton Bespalov, Manuel Houzet, Julia S. Meyer, Y.V. Nazarov Files PDF PhysRevB.93.104521.pdf 746.32 KB Close viewer /islandora/object/uuid:8cea7557-81b3-43d0-a77f-1a44c4ce60d5/datastream/OBJ/view