Semimetal-semiconductor transition and giant linear magnetoresistances in three-dimensional Dirac semimetal Bi0.96Sb0.04 single crystals

TL;DR

This study investigates the magnetotransport properties of Bi0.96Sb0.04 single crystals at the quantum critical point, revealing a magnetic-field induced phase transition and giant linear magnetoresistance, with potential applications in magnetoelectronic devices.

Contribution

It reports the first observation of a semimetal-semiconductor transition and giant linear magnetoresistance in 3D Dirac semimetal Bi0.96Sb0.04 at the quantum critical point.

Findings

Magnetic-field induced semimetal-semiconductor phase transition observed.

Giant magnetoresistance up to 6000% at 5 K and 300% at room temperature.

Magnetoresistance remains linear down to near zero field below 200 K.

Abstract

Three-dimensional (3D) Dirac semimetals are new quantum materials and can be viewed as 3D analogues of graphene. Many fascinating electronic properties have been proposed and realized in 3D Dirac semimetals, which demonstrates their potential applications in next generation quantum devices. Bismuth-antimony Bi1-xSbx can be tuned from a topological insulator to a band insulator through a quantum critical point at x ~ 4%, where 3D Dirac fermions appear. Here, we report on a magnetotransport study of Bi1-xSbx at such a quantum critical point. An unusual magnetic-field induced semimetal-semiconductor phase transition was observed in the Bi0.96Sb0.04 single crystals. In a magnetic field of 8 T, Bi0.96Sb0.04 single crystals show giant magnetoresistances of up to 6000% at low-temperature, 5 K, and 300% at room-temperature, 300 K. The observed magnetoresistances keep linear down to approximate zero-field when the temperature is below 200 K. Our experimental results are not only interesting for the fundamental physics of 3D Dirac semimetals, but also for potential applications of 3D Dirac semimetals in magnetoelectronic devices.