Real space Bogolubov-de Gennes equations study of the boson-fermion model

TL;DR

This study uses real space Bogolubov-de Gennes equations to analyze how impurities affect superconducting properties in the boson-fermion model, providing insights into inhomogeneities in high-temperature superconductors.

Contribution

It applies the real space Bogolubov-de Gennes approach to the boson-fermion model to investigate impurity effects on superconductivity in high-temperature superconductors.

Findings

Impurities cause significant local variations in the order parameter.

Disorder affects the density of states and superconducting coherence.

Results match experimental observations of inhomogeneities in HTS.

Abstract

The boson-fermion (BF) model has been proposed to describe superconductivity in short coherence length superconductors. In this work we use it to study impurity induced inhomogeneities in high temperature superconductors (HTS) as found in numerous scanning tunnelling measurements. The model has been formulated in real space and solved with help of Bogolubov-de Gennes approach. Disorder in the boson or fermion subsystem is directly coupled to the superconducting order parameter and leads to severe changes of superconducting properties like local order parameter and density of states. We present the results for many impurities randomly distributed over otherwise clean and periodic two-dimensional square lattice.