Density of states in a vortex core and the zero-bias tunneling peak

Abstract

Scanning-tunneling-microscope measurements by Hess et al. of the tunneling conductance into a superconducting vortex core show a pronounced peak at small bias. We show that this peak is due to the quasiparticle bound states in the core. A numerical (and approximately self-consistent) solution of the Bogoliubov–de Gennes equations yields the local density of states in the core, which resembles the tunneling conductance once we account for thermal broadening effects. We find additional structure in the local density of states which should be observable at lower temperatures.