Revealing surface states in In-doped SnTe superconducting nanoplates with low bulk mobility

TL;DR

This study demonstrates that In-doped SnTe nanoplates exhibit surface states detectable via magnetotransport, with reduced bulk mobility revealing topological surface effects, advancing the understanding of topological superconductivity in nanostructures.

Contribution

It shows that nanostructuring and doping-induced bulk mobility reduction can effectively reveal surface states in topological superconductors.

Findings

In-doped SnTe nanoplates are superconducting.

Linear magnetoresistance indicates surface states.

Surface states are confirmed by aging experiments.

Abstract

Indium (In) doping in topological crystalline insulator SnTe induces superconductivity, making In-doped SnTe a candidate for a topological superconductor. SnTe nanostructures offer well-defined nanoscale morphology and high surface-to-volume ratios to enhance surface effects. Here, we study In-doped SnTe nanoplates, InxSn1-xTe, with x ranging from 0 to 0.1 and show they superconduct. More importantly, we show that In doping reduces the bulk mobility of InxSn1-xTe such that the surface states are revealed in magnetotransport despite the high bulk carrier density. This is manifested by two-dimensional linear magnetoresistance in high magnetic fields, which is independent of temperature up to 10 K. Aging experiments show that the linear magnetoresistance is sensitive to ambient conditions, further confirming its surface origin. We also show that the weak antilocalization observed in InxSn1-xTe nanoplates is a bulk effect. Thus, we show that nanostructures and reducing the bulk mobility are effective strategies to reveal the surface states and test for topological superconductors.