Electron and hole contributions to normal-state transport in the superconducting system Sn$_{1-x}$In$_x$Te

TL;DR

This study investigates the electronic transport properties of indium-doped SnTe, revealing a carrier type transition and quantum oscillations linked to bulk Dirac-like hole pockets, enhancing understanding of its superconducting and topological features.

Contribution

It provides new insights into the electronic states and carrier dynamics in Sn$_{1-x}$In$_x$Te, especially the coexistence of hole and electron carriers and their relation to topological and superconducting properties.

Findings

Carrier type changes from hole-like to electron-like at x~0.25

Pronounced Shubnikov-de Haas oscillations observed at x=0.45

Evidence of weak anti-localization in magnetoresistance measurements

Abstract

Indium-doped SnTe has been of interest because the system can exhibit both topological surface states and bulk superconductivity. While the enhancement of the superconducting transition temperature is established, the character of the electronic states induced by indium doping remains poorly understood. We report a study of magneto-transport in a series of Sn$_{1-x}$In$_x$Te single crystals with $0.1\le x \le 0.45$. From measurements of the Hall effect, we find that the dominant carrier type changes from hole-like to electron-like at $x\sim0.25$; one would expect electron-like carriers if the In ions have a valence of $+3$. For single crystals with $x = 0.45$, corresponding to the highest superconducting transition temperature, pronounced Shubnikov-de Haas oscillations are observed in the normal state. In measurements of magnetoresistance, we find evidence for weak anti-localization (WAL). We attribute both the quantum oscillations and the WAL to bulk Dirac-like hole pockets, previously observed in photoemission studies, which coexist with the dominant electron-like carriers.