Low-temperature surface conduction in the Kondo insulator SmB$_6$

TL;DR

This study investigates the low-temperature transport in SmB$_6$, revealing a crossover from bulk to surface conduction below 4 K, supporting the existence of topological surface states in this Kondo insulator.

Contribution

It provides experimental evidence for topological surface states in SmB$_6$ by distinguishing surface conduction from bulk conduction at low temperatures.

Findings

Surface conduction dominates below 4 K

Bulk becomes fully insulating at low temperatures

Supports topological insulator behavior in SmB$_6$

Abstract

We study the transport properties of the Kondo insulator SmB$_6$ with a specialized configuration designed to distinguish bulk-dominated conduction from surface-dominated conduction. We find that as the material is cooled below 4 K, it exhibits a crossover from bulk to surface conduction with a fully insulating bulk. We take the robustness and magnitude of the surface conductivity, as is manifest in the literature of SmB$_6$, to be strong evidence for the topological insulator metallic surface states recently predicted for this material.