Anomalous scattering in superconducting indium-doped tin telluride

TL;DR

This study investigates how indium doping affects the electrical, magnetic, and structural properties of tin telluride, revealing the emergence of superconductivity and anomalous scattering phenomena at higher doping levels.

Contribution

It provides detailed experimental characterization of indium-doped SnTe, identifying the doping levels at which superconductivity and anomalous scattering occur, and proposes the material as a candidate charge Kondo system.

Findings

Superconductivity appears at indium concentrations above 6.1%.

Anomalous low-temperature scattering is observed at higher indium levels.

No magnetic impurities or localization effects are detected.

Abstract

Results of resistivity, Hall effect, magnetoresistance, susceptibility and heat capacity measurements are presented for single crystals of indium-doped tin telluride with compositions Sn$_{.988-x}$In$_x$Te where $0 \leq x \leq 8.4 %$, along with microstructural analysis based on transmission electron microscopy. For small indium concentrations, $x \leq 0.9 %$ the material does not superconduct above 0.3 K, and the transport properties are consistent with simple metallic behavior. For $x \geq 2.7 %$ the material exhibits anomalous low temperature scattering and for $x \geq 6.1 %$ bulk superconductivity is observed with critical temperatures close to 2 K. Intermediate indium concentrations $2.7% \leq x \leq 3.8%$ do not exhibit bulk superconductivity above 0.7 K. Susceptibility data indicate the absence of magnetic impurities, while magnetoresistance data are inconsistent with localization effects, leading to the conclusion that indium-doped SnTe is a candidate charge Kondo system, similar to thallium-doped PbTe.