Effect of Lead Substitution on LaO0.5F0.5BiS2

TL;DR

This study investigates how lead substitution affects the structural and superconducting properties of LaO0.5F0.5BiS2, revealing enhancements in superconductivity linked to structural instability, with specific anomalies observed at certain Pb concentrations.

Contribution

It demonstrates that Pb substitution enhances superconductivity in LaO0.5F0.5BiS2 and links this to structural instability, a novel insight not previously reported.

Findings

Pb substitution causes lattice anomalies at ~8-9%

Superconducting transition temperature increases with Pb

Resistivity anomaly at ~150K in La-based compound

Abstract

We examined Lead (Pb) Substitution effect on a single crystal of a layered superconductor LaO0.5F0.5BiS2. Pb concentration dependence of the lattice constant showed slight anomaly at about 8% and 9% substitution of Pb for Bi. These samples showed the enhancement of the superconducting transition temperature and the superconducting volume fraction. Furthermore, these samples showed the anomaly in the temperature dependence of the resistivity at about 150K. These results were not observed in Pb substituted NdO0.7F0.3BiS2. Therefore, the enhancement of the superconducting properties by Pb substitution is related to the structural instability for the pale perturbation in LaO0.5F0.5BiS2.