Large linear magnetoresistance in the Dirac semimetal TlBiSSe

TL;DR

This study reports large linear magnetoresistance in the 3D Dirac semimetal TlBiSSe, with findings suggesting a Hall field-related mechanism in a clean system, challenging previous inhomogeneity-based explanations.

Contribution

It demonstrates the occurrence of large linear MR in a clean 3D Dirac semimetal and explores its underlying mechanism, which is not due to inhomogeneity.

Findings

Large linear MR approaching 10,000% at 1.8 K and 14 T

Shubnikov-de Haas oscillations confirming 3D Dirac nature

MR diminishes rapidly above 30 K

Abstract

The mixed-chalcogenide compound TlBiSSe realizes a three-dimensional (3D) Dirac semimetal state. In clean, low-carrier-density single crystals of this material, we found Shubnikov-de Haas oscillations to signify its 3D Dirac nature. Moreover, we observed very large linear magnetoresistance (MR) approaching 10,000% in 14 T at 1.8 K, which diminishes rapidly above 30 K. Our analysis of the magnetotransport data points to the possibility that the linear MR is fundamentally governed by the Hall field; although such a situation has been predicted for highly-inhomogeneous systems, inhomogeneity does not seem to play an important role in TlBiSSe. Hence, the mechanism of large linear MR is an intriguing open question in a clean 3D Dirac system.