Topological transitions in electronic spectra: Crossover between Abrikosov and Josephson vortices

TL;DR

This paper investigates how the electronic spectrum of vortex lines in type-II superconductors changes during the transition from Abrikosov to Josephson vortices, revealing topological spectral transitions and new quasiparticle states.

Contribution

It introduces a theoretical analysis of topological transitions in vortex spectra caused by planar defects, highlighting the formation of new quasiparticle states and spectral features during the crossover.

Findings

Topological transition in quasiparticle spectrum at defect plane.

Formation of new quasiparticle states skipping or gliding along the defect.

Changes in spectral gaps influence vortex mobility and tunneling characteristics.

Abstract

The electronic structure of a vortex line trapped by a planar defect in a type-II superconductor is analyzed within the Bogoliubov-de Gennes theory. The normal reflection of electrons and holes at the defect plane results in the topological transition in the spectrum and formation of a new type of quasiparticle states skipping or gliding along the defect. This topological transition appears to be a hallmark of the initial stage of the crossover from the Abrikosov to the Josephson vortex type revealing in the specific behavior of the quantized quasiparticle levels and density of states. The increase in the resulting hard and soft gaps affects the vortex mobility along the defect plane and splitting of the zero bias anomaly in the tunneling spectral characteristics.