Quasiparticle spectrum of a type-II superconductor in a high magnetic field with randomly pinned vortices

TL;DR

This paper investigates how disorder affects the quasiparticle spectrum of a high-field, type-II superconductor, revealing that gapless superconductivity persists and exhibits topological features even with strong vortex pinning.

Contribution

It demonstrates that gapless superconductivity remains robust in disordered, high-field type-II superconductors and provides detailed calculations of the quasiparticle density of states under varying disorder levels.

Findings

Density of states at low energies increases with disorder

Gapless superconductivity persists despite strong disorder

Low-energy density of states ratio significantly increases with disorder

Abstract

We show that gapless superconductivity of a strongly type-II superconductor in a high magnetic field prevails in the presence of disorder, suggesting a topological nature. We calculate the density of states of the Bogoliubov-de Gennes quasiparticles for a two-dimensional inhomogeneous system in both cases of weak and strong disorder. In the limit of very weak disorder, the effect is very small and the density of states is not appreciably changed. As the disorder increases, the density of states at low energies increases and the ratio of the low-energy density of states to its maximum increases significantly.