Investigation of superconducting gap of high-entropy telluride AgInSnPbBiTe5

TL;DR

This study investigates the superconducting properties of high-entropy telluride AgInSnPbBiTe5 using muon spin relaxation, revealing strong-coupling superconductivity and long penetration depth, suggesting universal features among HE-type superconductors.

Contribution

First detailed muon spin relaxation study on high-entropy telluride superconductor AgInSnPbBiTe5 revealing its strong-coupling nature and long penetration depth.

Findings

Superconducting gap larger than weak-coupling prediction.

Long penetration depth of approximately 3.21 μm.

Strong-coupling superconductivity similar to other HE-type superconductors.

Abstract

We performed transverse-field muon spin relaxation/rotation (TF-{\mu}SR) on a high-entropy-type (HE-type) superconductor AgInSnPbBiTe5. The emergence of bulk superconducting states was confirmed from magnetic susceptibility, specific heat, and {\mu}SR. The superconducting gap 2{\Delta}(0) estimated from {\mu}SR was clearly larger than that expected from conventional weak-coupling phonon-mediated model, suggesting the strong-coupling nature of superconductivity. In addition, a long penetration depth of 3.21(7) {\mu}m was obtained. The strong-coupling nature of superconductivity and the long penetration depth are similar to the trends observed in the other HE-type superconductors (HE alloys and transition-metal zirconides), which may be universal feature of HE-type superconductors.