Effect of CuO chains on the local density of states in the vortex phase of YBa_2Cu_3O_7

TL;DR

This study investigates how CuO chains influence the local density of states in the vortex phase of YBa_2Cu_3O_7 using a tight-binding proximity model and self-consistent Bogolyubov-de Gennes calculations.

Contribution

It introduces a bilayer model that captures the effects of CuO chains on vortex core states, revealing additional anisotropic resonances.

Findings

Chains induce a second set of dispersing resonances.

Resonances are highly anisotropic.

Vortex core shape is distorted by chain effects.

Abstract

We examine the effects of the CuO chains on the density of states in the vortex phase in YBa_2Cu_3O_7, via a calculation based on the tight-binding proximity model. In this model, chain superconductivity results from single-electron hopping between the intrinsically-normal chains and intrinsically-superconducting CuO_2 planes. The calculations are based on self-consistent solutions of the Bogolyubov-de Gennes equations for a bilayer consisting of a single CuO_2 layer and a single CuO chain layer. We find that, in addition to the dispersing resonances found in single-layer models, the chains introduce a second set of dispersing resonances associated with the induced gap in the chain layer. These new resonances are highly anisotropic and distort the vortex core shape.