Impurity Effects on Bound States in the Vortex Core of Topological S-wave Superconductor

Abstract

We study the impurity effects on the Caroli-de Gennes-Matricon (CdGM) states, particularly on the level spacings in a vortex core in topological s-wave superconductor (SC) by two means, numerically and analytically. The topological s-wave SC belongs to the same class as a chiral p-wave SC and thus there are two inequivalent vortices in terms of any symmetry operation. We take into account this inequivalence and numerically calculate the scattering rates based on an improved version of Kopnin-Kravtsov (iKK) scheme, which enables us to treat the discrete levels in the presence of white-noise disorder. We also construct the Andreev equation for the topological s-wave SC and obtain the Andreev bound states analytically. We use a correspondence between the wave functions for the Bogoliubov-de Gennes equation and the Andreev equation in the iKK scheme and deduce the formula of scattering rates described by the wave function for the Andreev equation. With this formula, we discuss the origin of impurity scattering rates for CdGM states of topological s-wave SC and the dependence on the types of vortices related to the inequivalence.

10 pages, 6 figures

References in corpus (4)

• Non-Abelian Anyons and Topological Quantum Computation
• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• Classification of topological insulators and superconductors in three spatial dimensions
• Robustness of Majorana Modes and Minigaps in a Spin-Orbit-Coupled Semiconductor-Superconductor Heterostructure

Cited by in corpus (8)

• Manifestation of chirality in the vortex lattice in a two-dimensional topological superconductor
• Self-consistent study of Abelian and non-Abelian order in a two-dimensional topological superconductor
• Robust zero-energy bound states around a pair-density-wave vortex core in locally noncentrosymmetric superconductors
• Vortex pinning by the point potential in topological superconductors: a scheme for braiding Majorana bound states
• Chiral Majorana edge states in the vortex core of a $p+ip$ Fermi superfluid
• Charged and uncharged vortices in quasiclassical theory
• Coherence Effects of Caroli-de Gennes-Matricon Modes in Nodal Topological Superconductors
• Quantum interference among vortex bound states in superconductors