Revealing Surface States in In-Doped SnTe Nanoplates with Low Bulk Mobility

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, In_<i>x</i>Sn_1–<i>x</i>Te, with <i>x</i> ranging from 0 to 0.1 and show they superconduct. More importantly, we show that In doping reduces the bulk mobility of In_<i>x</i>Sn_1–<i>x</i>Te 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 In_<i>x</i>Sn_1–<i>x</i>Te 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