Shadow on the wall cast by an Abrikosov vortex

TL;DR

This paper investigates how a single Abrikosov vortex near a superconductor boundary affects the zero-energy quasiparticle states, revealing a stable shadow-like suppression of the density of states that impacts tunneling properties.

Contribution

It demonstrates the effect of a vortex on the zero-energy density of states near a boundary, showing a stable shadow effect across various models and conditions.

Findings

Splitting of the zero-energy peak near the vortex boundary

Suppression of zero-energy density of states in a shadow region

Effect persists across different vortex models and conditions

Abstract

At the surface of a d-wave superconductor, a zero-energy peak in the quasiparticle spectrum can be observed. This peak appears due to Andreev bound states and is maximal if the nodal direction of the d-wave pairing potential is perpendicular to the boundary. We examine the effect of a single Abrikosov vortex in front of a reflecting boundary on the zero-energy density of states. We can clearly see a splitting of the low-energy peak and therefore a suppression of the zero-energy density of states in a shadow-like region extending from the vortex to the boundary. This effect is stable for different models of the single Abrikosov vortex, for different mean free paths and also for different distances between the vortex center and the boundary. This observation promises to have also a substantial influence on the differential conductance and the tunneling characteristics for low excitation energies.