Discrete vortex bound states with a Van Hove singularity in the vicinity of the Fermi level

Abstract

Abstract A theoretical study on discrete vortex bound states is carried out near a vortex core in the presence of a Van Hove Singularity (VHS) near the Fermi level by solving Bogoliubov-de Gennes (BdG) equations. When the VHS lies exactly at the Fermi level and also at the middle of the band, a zero-energy state and other higher-energy states whose energy ratios follow integer numbers emerge. These discrete vortex bound state peaks undergo a splitting behavior when the VHS or Fermi level moves away from the middle of the band. Such a splitting behavior will eventually lead to a new arrangement of quantized vortex core states whose energy ratios follow half-odd-integer numbers.