Influence of impurities on electronic structure in cuprate superconductors

TL;DR

This paper investigates how impurities affect the electronic structure of cuprate superconductors using a microscopic scattering model and self-consistent calculations, revealing their role in modifying quasiparticle behavior and superconducting gap properties.

Contribution

It introduces a detailed microscopic model to analyze impurity scattering effects on cuprate superconductors' electronic structure, combining self-energy evaluations with experimental comparisons.

Findings

Impurity scattering renormalizes quasiparticle bands and reduces their lifetime.

Impurity effects cause deviations from d-wave superconducting gap symmetry.

The electronic structure features are influenced by both electron correlation and impurity scattering.

Abstract

The impurity is inherently manifest in cuprate superconductors, as cation substitution or intercalation is necessary for the introduction of charge carriers, and its influence on the electronic state is at the heart of a great debate in physics. Here based on the microscopic octet scattering model, the influence of the impurity scattering on the electronic structure of cuprate superconductors is investigated in terms of the self-consistent T-matrix approach. The impurity scattering self-energy is evaluated firstly in the Fermi-arc-tip approximation of the quasiparticle excitations and scattering processes, and the obtained results show that the decisive role played by the impurity scattering self-energy in the particle-hole channel is the further renormalization of the quasiparticle band structure with a reduced quasiparticle lifetime, while the impurity scattering self-energy in the particle-particle channel induces a strong deviation from the d-wave behaviour of the superconducting gap, leading to the existence of a finite gap over the entire electron Fermi surface. Moreover, these impurity scattering self-energies are employed to study the exotic features of the line-shape in the quasiparticle excitation spectrum and the autocorrelation of the quasiparticle excitation spectra, and the obtained results are then compared with the corresponding experimental data. The theory therefore also indicates that the unconventional features of the electronic structure in cuprate superconductors is generated by both the strong electron correlation and impurity scattering.