Quasiparticle spectra in the vicinity of a d-wave vortex

TL;DR

This paper analyzes how quasiparticle spectra and tunneling conductance near a d-wave vortex vary with position and angle, considering disorder and tunneling anisotropy effects, and predicts conductance anisotropy patterns.

Contribution

It provides a detailed analysis of quasiparticle spectral evolution near a d-wave vortex, incorporating disorder and tunneling anisotropy, and predicts conductance anisotropy features.

Findings

Disorder and tunneling anisotropy obscure the expected 1/r tail in conductance.

Predicted anisotropy in tunneling conductance around the vortex core.

Connection established between tunneling matrix structure and conductance patterns.

Abstract

We discuss the evolution of the local quasiparticle spectral density and the related tunneling conductance measurable by the scanning tunneling microscope, as a function of distance r and angle \theta from the vortex core in a d_{x^2-y^2} superconductor. We consider the effects of electronic disorder and of a strongly anisotropic tunneling matrix element, and show that in real materials they will likely obscure the ~1/r asymptotic tail in the zero-bias tunneling conductance expected from the straightforward semiclassical analysis. We also give a prediction for the tunneling conductance anisotropy around the vortex core and establish a connection to the structure of the tunneling matrix element.