Coalescence of Impurity Strontium Atoms in Lightly-Substituted Samples of Lanthanum Cuprate

TL;DR

This study investigates how impurity strontium atoms coalesce in lightly-doped lanthanum cuprates, revealing their effects on electron transport, magnetic properties, and superconducting behavior through experimental and numerical analysis.

Contribution

It introduces a phenomenological model linking impurity concentration with scattering effects and superconducting profiles in La-based cuprates, advancing understanding of impurity coalescence.

Findings

Dilute Sr leads to a constant scattering profile with a sharp zero-frequency peak.

Higher Sr concentration broadens the zero-frequency peak due to self-consistent scattering.

Very low impurity levels result in a narrow, dominant zero-frequency peak.

Abstract

By comparing experimental results obtained in the study of the electron transport and magnetic properties of samples of lightly strontium-substituted lanthanum cuprates and the results of a previously published numerical analysis in the reduced elastic scattering space (RPS) of the elastic scattering cross-section, we construct a phenomenological classical self-consistent strong-binding energy density profile in the superconducting $La_{2-x}Sr_xCuO_4$ cuprate. It is found that the imaginary part of the reduced phase scattering space can be zero, almost constant, or strongly self-consistent, depending on the Sr substituted concentration. If the Sr atomic concentration is dilute, a constant imaginary part of the elastic scattering cross-section brings a sub-melted coalescent superconducting metallic profile similar to the one with a constant scattering lifetime in the metallic state of normal metals, except for the unitary narrow, sharp peak at zero frequency. A self-consistent broadening of this peak occurs for a higher concentration of Sr atoms, and finally, for very small amounts of nonmagnetic dirt, only the narrow unitary peak prevails around the zero frequency.