Multiquantum vortices in superconductors: Electronic and scanning tunneling microscopy spectra

Abstract

Superconducting quasiparticle excitation spectra are computed for m times quantized flux lines using a self-consistent Bogoliubov--de Gennes approach. We find m discrete branches of bound-state solutions in the spectrum, corresponding to different values of the quasiparticle angular momentum. Owing to the bound states, the scanning tunneling microscopy spectrum of the vortex is predicted to display m rows of peaks as a function of the distance from the vortex axis.