Surface-induced positive planar Hall effect in topological Kondo insulator SmB6 microribbons

TL;DR

This study demonstrates a positive planar Hall effect in SmB6 microribbons, attributed to topological surface states, with the effect's magnitude varying with temperature, supporting the topological nature of these surface states.

Contribution

It provides experimental evidence of surface-induced positive PHE in SmB6, indicating the topological character of its surface states through magneto-transport measurements.

Findings

Positive PHE increases as temperature decreases below 5 K.

Negative PHE observed in bulk states at high temperatures.

Surface states exhibit a much stronger PHE than bulk states.

Abstract

Whether the surface states in SmB6 are topological is still a critical issue in the field of topological Kondo insulators. In the magneto-transport study of single crystalline SmB6 microribbons, we have revealed a positive planar Hall effect (PHE), the amplitude of which increases dramatically with decreasing temperatures but saturates below 5 K. This positive PHE is ascribed to the surface states of SmB6 and expected to arise from the anisotropy in lifting the topological protection from back-scattering by the in-plane magnetic field, thus suggesting the topological nature of surface states in SmB6. On the contrary, a negative PHE is observed for the bulk states at high temperatures, which is almost three orders of magnitudes weaker than the surface-induced positive PHE.