Anomalous Hall effect and negative longitudinal magnetoresistance in half-Heusler topological semimetal candidates TbPtBi and HoPtBi

Abstract

Half-Heusler compounds have attracted significant attention because of their topologically non-trivial electronic structure, which leads to unusual electron transport properties. We thoroughly investigated the magnetotransport properties of high-quality single crystals of two half-Heusler phases, TbPtBi and HoPtBi, in pursuit of the characteristic features of topologically non-trivial electronic states. Both studied compounds are characterized by the giant values of transverse magnetoresistance with no sign of saturation in magnetic field up to 14 T. HoPtBi demonstrates the Shubnikov-de Haas effect with two principal frequencies, indicating a complex Fermi surface; the extracted values of carrier effective masses are rather small, 0.18 m e and 0.27 m e. The investigated compounds exhibit negative longitudinal magnetoresistance and anomalous Hall effect, which likely arise from a nonzero Berry curvature. Both compounds show strongly anisotropic magnetoresistance, that in HoPtBi exhibits a butterfly-like behavior.

Large Magneto‐Transverse and Longitudinal Thermoelectric Effects in the Magnetic Weyl Semimetal TbPtBi

“…Previous studies suggest that large anomalous Hall angle of TbPtBi results from large net Berry curvature induced by Weyl points or anti-crossing of spinsplit bands. [25][26][27][28] In our study, as suggested by DFT calculation results shown in Figure 1c, the large net Berry curvature at Fermi level is mainly contributed by Weyl points. To further confirm this point, we performed measurement on longitudinal magneto-resistance (LMR) (Figure 3a,b) and planar Hall resistance (PHE) (Figure 3c,d).…”

“…Due to large net Berry curvature at the Fermi level, TbPtBi exhibits large anomalous Hall conductivity and anomalous Hall angle (Figure S3, Supporting Information), which further enhances total Hall angle (Figure 1d) and are consistent with previous reports. [25][26][27][28] Moreover, the maximum total Hall angle of ≈3 at 2 K and 14 Tesla is larger than previous reports [25][26][27][28] and some other magnetic topological materials, such as Co 3 Sn 2 S 2 , Mn 3 Ge, and GdPtBi. [29][30][31] Based on Mott formula and linear response equation, the transverse thermopower can be expressed as [32] In the case where Hall angle is energy dependent, taking a first-order approximation of above formula, the transverse thermopower can be rewritten as…”

“…TbPtBi crystallizes in a cubic structure with space group F-43m, as shown in Figure 1a. Along with [111] crystal direction, Tb atoms are inferred to exhibit a type-II antiferromagnetic ordering [25][26][27][28] and the transition occurs at 3.3 K (Figure S2a, Supporting Information). Previous studies suggest that TbPtBi is an antiferromagnetic topological insulator and a magnetic field induced topological transition happens when Tb moment is aligned along with [100] crystal direction owing to the spin-degenerate bands splitting and strong-SOC induced band inversion.…”

Giant magnetoresistance, Fermi surface topology, Shoenberg effect and vanishing quantum oscillations in type-II Dirac semimetal candidates MoSi$_2$ and WSi$_2$

“…This leads to large anisotropic magnetoresistance (AMR = [ρ(90 • ) − ρ(0 • )]/ρ(0 • )) which is equal to −95% for WSi 2 and −98% for MoSi 2 at T = 2 K and in B = 14 T. The magnitudes of AMR are larger than those we reported previously for rare earth monoantimonides [16,49] and half-Heulser bismuthides. [72][73][74] The origin of this huge AMR can be ascribed to the highly anisotropic Fermi surface of the studied compounds. Large AMR has been previously observed in materials with XMR, like bismuth, [75] graphite [76] and WTe 2 .…”

Local origin of the strong field-space anisotropy in the magnetic phase diagrams of Ce1−xLaxB6 measured in a rotating magnetic field

“…For example, it is very pronounced in RFe 2 and RCo 2 Laves phases [6,7] (R = rare earth), where it could be satisfactorily explained by means of single-ion crystal-field theory [8]. From more recent examples, strong anisotropy in the fieldangular dependence of magnetoresistance, measured upon continuously rotating the direction of an external magnetic field B, was reported for the half-Heusler compounds TbPtBi and HoPtBi [9,10] and for several RE dodecaborides [11][12][13][14][15][16][17], most prominently pure and doped TmB 12 and ErB 12 . In TmB 12 and its doped derivatives Tm 1−x Lu x B 12 and Tm 1−x Yb x B 12 , the field-angular magnetic phase diagrams in the B ⊥ 110 plane, suggested by the magnetotransport measurements, resemble a Maltese cross [12][13][14][15][16][17] with very sharp straight transition lines, separating different antiferromagnetic (AFM) phases that exist between 0 and 3 T in sectors around the [001], [111], and [110] field directions.…”