Large spectral gap and impurity-induced states in a two-dimensional Abrikosov vortex

Article

关键词: DENSITY-OF-STATES;    SCANNING TUNNELING SPECTROSCOPY;    QUASI-PARTICLE SPECTRUM;    BOUND-STATES;    ELECTRONIC-STRUCTURE;    CORE STRUCTURE;    LOCAL-DENSITY;    LOW-ENERGY;    SUPERCONDUCTORS;    ABSORPTION;   

DOI  :  10.1103/PhysRevB.103.024510

来源: SCIE

【 摘 要 】

We study the subgap spectrum of a 2D Abrikosov vortex in an s-wave superconductor in the absence and presence of a point impurity. By solving the Eilenberger equations without impurity for two models of the vortex (including a self-consistent one), we find multiple subgap spectral branches. The number of these branches may be arbitrarily large provided that the magnetic field screening length is large enough. The quasiclassical spectrum of the vortex has a local gap with a width of the order of the bulk gap and a spatial extent of several coherence lengths. The existence of such a gap is the prerequisite for the appearance of discrete impurity-induced states. Within the Gor'kov equations formalism, we find that a single impurity induces up to four discrete quasiparticle states in the vortex. The energies and wave functions of the impurity states are calculated for different parameters. We claim that most of the predicted spectral features can be observed in scanning tunnel spectroscopy experiments.

【 授权许可】

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