Large low-field positive magnetoresistance in nonmagnetic half-Heusler ScPtBi single crystal

Abstract

High-quality nonmagnetic half-Heusler ScPtBi single crystals were synthesized by a Bi self-flux method. This compound was revealed to be a hole-dominated semimetal with a large low-field magnetoresistance up to 240% at 2K in a magnetic field of 1T. Magneto-transport measurements demonstrated that the large low-field magnetoresistance effect resulted from the coexistence of field-induced metal-semiconductor transition and weak-antilocalization effect. Moreover, Hall measurements indicated that ScPtBi single crystal showed a high mobility over a wide temperature region even up to room temperature (4050 cm 2 V -1 s -1 at 2K -2016 cm 2 V -1 s -1 at 300K).These findings not only suggest the nonmagnetic ScPtBi semimetal a potential material candidate for applications in high-sensitivity magnetic sensors, but also are of great significance to comprehensively understand the rare-earth based half-Heusler compounds.Recently, searching for new materials with semimetallic features in electronic structure protected by the interplay of symmetry and topology has attracted increasing attention, following the observation of large non-saturation magnetoresistance (MR) in a variety of nonmagnetic semimetals such as Cd 3 As 2 , 1 TaAs, 2 NbP, 3 and WTe 2 . 4 Electronic transport in heavy half-Heusler compounds is distinguished from others by the fact that the strong spin-orbit coupling (SOC) induces many fascinating phenomena, such as the heavy fermion behavior, 5 noncentersymetry superconductors, 6-8 possible topological insulators, 9-13 large positive MR, [14][15][16] and extremely high mobility, 17 which are of great significance to the applied physics field.According to band structure calculations, half-Heusler ScPtBi is predicted to show similar band inversion to that of HgTe. 9, 10, 13 Its topological properties can be created by applying strain or designing an appropriate quantum well structure. 9 Moreover, this material possesses nearly linear dispersion relation of bulk band along with zero gap, 13 which is usually associated with large MR effect and high mobility behavior. [1][2][3][4]14,15,17,18 Although the growth of many heavy half-Heusler compounds (such as LuPdBi, 6,16, 19 LuPtBi, 7 LuPtSb,15,20,21 and YPtBi 8 ) have been previously reported, the synthesis of ScPtBi (no matter polycrystal or single crystal) is unsuccessful thus far since this compound is proposed to show a weaker thermodynamic stability. 22,23 In this work, we report on the growth and magneto-transport properties of high-quality nonmagnetic ScPtBi single crystal. Intriguingly, the metal-semiconductor transition coexists with the weak antilocalization (WAL) effect in this material, which results in a large low-field positive MR (240% at 2K -150% at 100K) in a magnetic field of 1T.Single crystals of ScPtBi were synthesized by using excess Bi as the flux in a molar ratio of Sc:Pt: Bi = 1:1:10. The starting materials were mixed together and placed in an alumina crucible with the one having higher melting temperatures on the bottom. This process was handle...

Negative longitudinal magnetoresistance as a sign of a possible chiral magnetic anomaly in the half-Heusler antiferromagnet DyPdBi

“…In weak fields, they rapidly grow with increasing B. Similar behavior has been observed in several HH phases and ascribed to weak antilocalization effect 31,32,37,[43][44][45] . At certain values of B, both LMR and TMR attain maximum, then monotonically decrease and become negative.…”

Low‐Temperature Eutectic Synthesis of PtTe2 with Weak Antilocalization and Controlled Layer Thinning

“…As shown in Figure e, the HLN theory (solid lines) agrees well with experimental data (symbols). Similar to the previous reports, α is much larger than that in 2D systems due to bulk effect . Through the fittings, we extracted the corresponding phase decoherence length , with results shown in Figure f.…”

Magnetoresistance of compensated semimetals in confined geometries

“…A fast growing number of experiments on novel twocomponent materials exhibit unconventional transport properties in magnetic field: (i) linear magnetoresistance (LMR) was reported in graphene and topological insulators close to charge neutrality [28][29][30][31][32][33][34][35][36] as well as in narrowgap semiconductors 37 , bismuth films 38,39 , and threedimensional (3D) silver chalcogenides [40][41][42] (ii) giant (and sometimes also linear) magnetoresistance was identified in semimetals WTe [43][44][45] 51 and many others [52][53][54][55][56][57] ; (iii) finally, the widely discussed negative magnetoresistance was found in Weyl semimetals and related materials [58][59][60][61][62][63][64][65][66][67][68] . Moreover, negative magnetoresistance may by regarded as a "smoking gun" for detecting a Weyl semimetal 69,70 , although experiment 71,72 shows the existence of the effect in "non-Dirac" materials as well.…”