Surface-state-dominated transport in crystals of the topological crystalline insulator In-doped Pb$_{1-x}$Sn$_x$Te

TL;DR

This study demonstrates that indium-doped Pb$_{1-x}$Sn$_x$Te crystals exhibit high bulk resistivity and surface-state-dominated transport, providing a platform to explore topological surface states in crystalline insulators.

Contribution

It reports the synthesis and characterization of bulk-insulating topological crystalline insulators with dominant surface state conduction, advancing understanding of surface transport in these materials.

Findings

High bulk resistivity achieved in indium-doped Pb$_{1-x}$Sn$_x$Te

Surface states dominate transport up to 30 K

Thickness-dependent transport confirms surface conduction

Abstract

Three-dimensional topological insulators and topological crystalline insulators represent new quantum states of matter, which are predicted to have insulating bulk states and spin-momentum-locked gapless surface states. Experimentally, it has proven difficult to achieve the high bulk resistivity that would allow surface states to dominate the transport properties over a substantial temperature range. Here we report a series of indium-doped Pb$_{1-x}$Sn$_x$Te compounds that manifest huge bulk resistivities together with strong evidence of topological surface states, based on thickness-dependent transport studies and magnetoresistance measurements. For these bulk-insulating materials, the surface states determine the resistivity for temperatures approaching 30 K.