Anisotropic electrical and thermal magnetotransport in the magnetic semimetal GdPtBi

Abstract

The half-Heusler rare-earth intermetallic GdPtBi has recently gained attention due to peculiar magnetotransport phenomena that have been associated with the possible existence of Weyl fermions, thought to arise from the crossings of spin-split conduction and valence bands. On the other hand, similar magnetotransport phenomena observed in other rare-earth intermetallics have often been attributed to the interaction of itinerant carriers with localized magnetic moments stemming from the 4 f shell of the rare-earth element. In order to address the origin of the magnetotransport phenomena in GdPtBi, we performed a comprehensive study of the magnetization, electrical, and thermal magnetoresistivity on two single-crystalline GdPtBi samples. In addition, we performed an analysis of the Fermi surface via Shubnikov-de Haas oscillations in one of the samples and compared the results to ab initio band structure calculations. Our findings indicate that the electrical and thermal magnetotransport in GdPtBi cannot be solely explained by Weyl physics and is strongly influenced by the interaction of both itinerant charge carriers and phonons with localized magnetic Gd ions and possibly also paramagnetic impurities.

Large magnetothermopower and anomalous Nernst effect in HfTe5

“…An alternative signature of the chiral anomaly was found in the thermoelectric properties in Cd 3 As 2 studied by Jia et al [5], showing that this approach bears more promise. Very recently, a new heat-transport mechanism called chiral zero sound has been predicted in Weyl semimetals [11] and could be used to explain the observed giant thermal conductivity in Weyl semimetal TaAs [12] and anomalous heat current in GdPtBi [13]. Here, we report our systematic study of the thermoelectric properties (both Seebeck and Nernst effects) of layered Hafnium pentatelluride (HfTe 5 ) single crystals and show that the observed results are consistent with a nontrivial electronic structure.…”

Chiral anomalies induced transport in Weyl metals in quantizing magnetic field

“…However, in the limiting case of βμ → ∞, α s zz → 0, consistent with the results of Refs. [27,52]. As a consequence of this vanishing α, the magnetic-field-induced change in the Seebeck coefficient, S = ασ −1 , is equal to the magnetic-field-induced change in σ .…”

“…The carriers of the lowest LLs have a constant velocity, and are either left movers (for s = 1) or right movers (for s = −1). Next, we discuss the origin of quantum anomalies from the lowest chiral LLs and explore their manifestation in electric and thermal magnetotransport experiments in WM [25,27,29,41,52].…”

“…Thus, the existence of the chiral LLs is an essential ingredient to obtain the nonzero charge and energy currents for each node even in equilibrium. These chiral currents are in turn related to the CAs in WMs [27,29,52]. We had earlier derived equations similar to Eqs.…”

“…The quantities C s 0 , C s 2 , and C s 1 are known as the coefficient of the chiral (or axial) anomaly [41], the coefficient of the mixed chiral (or axial) gravitational anomaly [25,27,52] and the coefficient of the thermal chiral (or axial) anomaly [29], respectively. We emphasize that the coefficient C s 1 vanishes in the βμ → ∞ limit and has been relatively unexplored.…”