Cluster structure of superconducting phase and the nature of peaks in the doping dependences of the London penetration depth in iron pnictides

TL;DR

This paper presents a model explaining the dome-shaped phase diagrams and peaks in London penetration depth in iron pnictides, emphasizing local doping and cluster structures despite simplified assumptions.

Contribution

It introduces a simple model that accurately predicts superconducting domes and explains peaks in penetration depth based on doping and cluster structures.

Findings

Model accurately predicts positions of superconducting domes.

Explains the nature and doping dependence of peaks in London penetration depth.

Despite simplicity, captures key features of phase diagrams.

Abstract

The mechanism of formation of dome-like phase diagrams and the features of magnetic field penetration in iron pnictides with hetero- and isovalent doping are considered within the framework of the previously proposed model, which assumes the local character of doping and the cluster structure of resulted superconducting phase. It is shown that the proposed model, despite its simplicity and neglect of the features of the electronic structure, makes it possible not only to accurately calculate the positions of superconducting domes on the phase diagrams of specific HTSC compounds, but also to explain the nature and position of sharp peaks in the London penetration depth depending on the doping level.