Robust Surface Hall Effect and Nonlocal Transport in SmB6: Indication for an Ideal Topological Insulator

TL;DR

This paper demonstrates that SmB6 exhibits robust, thickness-independent surface Hall effects and nonlocal transport, confirming its status as an ideal topological insulator with a truly insulating bulk and metallic surface.

Contribution

It provides experimental evidence of a robust metallic surface in SmB6 with thickness-independent transport properties, advancing the understanding of topological Kondo insulators.

Findings

Surface Hall effects are thickness-independent in SmB6.

Nonlocal transport persists despite mechanical abrasion.

Surface states are robust against perturbations.

Abstract

A topological insulator (TI) is an unusual quantum state in which the insulating bulk is topologically distinct from vacuum, resulting in a unique metallic surface that is robust against time-reversal invariant perturbations. These surface transport properties, however, remains difficult to be isolated from the bulk in existing TI crystals (Bi2Se3, Bi2Te3 and Sb2Te3) due to impurity caused bulk conduction. We report in large crystals of topological Kondo insulator (TKI) candidate material SmB6 the thickness-independent surface Hall effects and non- local transport, which are robust against perturbations including mechanical abrasion. These results serve as proof that at low temperatures SmB6 has a robust metallic surface that surrounds a truly insulating bulk, paving the way for transport studies of the surface state in this proposed TKI material. (xia.jing@uci.edu).