Exceptionally large anomalous Hall effect due to anticrossing of spin-split bands in the antiferromagnetic half-Heusler compound TbPtBi

Abstract

We have investigated magnetotransport properties and the topological electronic structure of the half-Heusler compound TbPtBi. Our experiments reveal an exceptionally large anomalous Hall effect (AHE) in the canted antiferromagnetic state of TbPtBi with the anomalous Hall angle (AHA) reaching ~0.68-0.76, which is a few times larger than the previously reported record in GdPtBi. First-principles electronic structure and the associated anomalous Hall conductivity were computed in order to interpret the experimental results. Our analysis shows that the AHE in TbPtBi does not originate from the Weyl points but that it is driven by the large net Berry curvature produced by the anticrossing of spin-split bands near the Fermi level in TbPtBi.

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

“…The maximum value tan Θ AH = 0.23 was found at T = 2 K in B = 1.78 T, and it is somewhat smaller than that reported before for TbPtBi. 32,33 tan Θ AH decreases with temperature increasing and the maximum position shifts to higher magnetic fields, in agreement with the literature data. 28,32,33 In the case of HoPtBi, the above method of extracting, which was also frequently used in recent studies, 28,32,33,49 appeared ineffective, and hence a different approach was applied.…”

“…32,33 tan Θ AH decreases with temperature increasing and the maximum position shifts to higher magnetic fields, in agreement with the literature data. 28,32,33 In the case of HoPtBi, the above method of extracting, which was also frequently used in recent studies, 28,32,33,49 appeared ineffective, and hence a different approach was applied. First, σ xy (B) was fitted with the single-band Drude model in the magnetic field range from 3 T to 14 T. The twoband Drude model was over-parametrised relative to the data set, and therefore could not be used for the experimental data approximation.…”

“…Their chemical composition was investigated on a FEI scanning electron microscope equipped with an EDAX Genesis XM4 spectrometer. The obtained chemical compositions Tb 33 Bi 33.12 were very close to nominal ones. X-ray diffraction experiments, performed on powdered single crystals, confirmed the MgAgAs-type crystal structure with the lattice parameters a = 6.665 Å and a = 6.632 Å for TbPtBi and HoPtBi, respectively, in good agreement with the literature data.…”

“…10,51 Remarkably, non-linear ρ xy (B) is also a strong indication of AHE. 28,33,49 In an attempt to determine the origin of the Hall effect in the studied compounds, we used the multi-band Drude model:…”

“…[30][31][32][33][34] TbPtBi was recently reported to demonstrate negative LMR and anomalous Hall angle (AHA), whereas only the former phenomenon was found in HoPtBi. 32,33 Our thorough investigations of the electrical transport and thermodynamic properties (magnetization and specific heat) of both materials were carried out on highquality single crystals. The observation of AHE and negative LMR strongly supports the existence of topologically nontrivial states in the two phases.…”