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

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 Bi 1−x Sb x 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 Bi 1−x Sb x at such a quantum critical point. An unusual magnetic-field induced semimetal-semiconductor phase transition was observed in the Bi 0.96 Sb 0.04 single crystals. In a magnetic field of 8 T, Bi 0.96 Sb 0.04 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.

Three-dimensional topological critical Dirac semimetal in AMgBi(A= K, Rb, Cs)

“…Na 3 Bi and Cd 3 As 2 have been predicted to be three-dimensional (3D) linear DSs theoretically 14,15 and have been verified by angle-resolved photoemission spectroscopy (ARPES) measurements 21,22 . In transport experiments, Cd 3 As 2 and several other DSs exhibit strong linear magnetoresistance 23,24 , which is also a strong evidence for DSs.In this Letter, we propose, by using first principles calculation, a family of materials, AMgBi, as topological semimetals that lie in between the type-I and the type-II Dirac semimetals, where A is an alkaline metal (A=K, Rb, Cs). While KMgBi, which has been synthesized 25 , is a type-I Dirac semimetal, both RbMgBi and CsMgBi, are both type-II Dirac semimetals.…”

“…Na 3 Bi and Cd 3 As 2 have been predicted to be three-dimensional (3D) linear DSs theoretically 14,15 and have been verified by angle-resolved photoemission spectroscopy (ARPES) measurements 21,22 . In transport experiments, Cd 3 As 2 and several other DSs exhibit strong linear magnetoresistance 23,24 , which is also a strong evidence for DSs.…”

Feature Behavior of Resistivity in Bi Foils Obtained by a Melt Spinning Method

“…The rhombohedral crystal structure of Bi is very sensitive to external influences, including heat field changes [20][21][22][23][24]. Bi and Bi1-xSbx alloys of single crystals, which are used for the investigation of physical and thermoelectric properties, have been grown by zone melting, the Bridgman and Czochralski methods [25][26][27][28][29]. A quartz ampoule used in zone melting and the Bridgman method, however, limits Bi expansion in crystal growth, creating large internal tensions in the single crystal that decreases its electro-physical properties.…”

Progress in Epitaxial Thin‐Film Na3Bi as a Topological Electronic Material

“…Accidental Dirac materials have been both predicted in theoretical calculations, [21][22][23] and verified experimentally. [24][25][26][27][28][29][30] In general, though, the accidental degeneracy requires fine-tuning of parameters, as the superposition of two Weyl nodes generically results in band hybridization and gap opening. This difficulty can be removed by protecting the degeneracy by a further space-group symmetry.…”