Superconductivity induced by In substitution into the topological crystalline insulator Pb(0.5)Sn(0.5)Te

TL;DR

This study demonstrates that substituting indium into the topological crystalline insulator Pb0.5Sn0.5Te induces superconductivity, with a maximum transition temperature of 4.7 K at an indium concentration of 0.30, suggesting potential for topological superconductivity.

Contribution

It provides systematic experimental evidence on how indium substitution affects the crystal structure and induces superconductivity in Pb0.5Sn0.5Te, identifying the solubility limit and optimal doping level.

Findings

Superconductivity appears at indium content around 0.30.

Maximum Tc of 4.7 K at x=0.30.

Crystal structure remains rock salt up to x~0.30.

Abstract

Indium substitution turns the topological crystalline insulator (TCI) Pb$_{0.5}$Sn$_{0.5}$Te into a possible topological superconductor. To investigate the effect of the indium concentration on the crystal structure and superconducting properties of (Pb$_{0.5}$Sn$_{0.5}$)$_{1-x}$In$_{x}$Te, we have grown high-quality single crystals using a modified floating-zone method, and have performed systematic studies for indium content in the range $0\leq x\leq 0.35$. We find that the single crystals retain the rock salt structure up to the solubility limit of indium ($x\sim0.30$). Experimental dependences of the superconducting transition temperature ($T_c$) and the upper critical magnetic field ($H_{c2}$) on the indium content $x$ have been measured. The maximum $T_c$ is determined to be 4.7 K at $x=0.30$, with $\mu_0H_{c2}(T=0)\approx 5$ T.