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

Magnetotransport investigation of a half-Heusler antiferromagnet DyPdBi revealed hallmark features of Weyl semimetal: huge negative longitudinal magnetoresistance and planar Hall effect. Both effects have recently been linked to a chiral magnetic anomaly—axial charge pumping between Weyl nodes. Magnetoresistance (MR) of single crystals of DyPdBi is very pronounced. In magnetic field longitudinal to electrical current direction it reaches $-80\%$ and its relative difference with respect to that measured in transverse field (expressed as anisotropic magnetoresistance) is extremely strong: $-60\%$ at 10 K and 14 T. The planar Hall effect in DyPdBi depends on temperature and magnetic field in nonmonotonous way, which has not been previously reported. We compare magnetoresistance measured with voltage contacts on midline of the sample with that measured with contacts on its edge, and show that the role of current-jetting, an extrinsic source of anisotropic negative magnetoresistance, is marginal. We discuss that nature of the compound and sample quality exclude intrinsic sources of negative and anisotropic magnetoresistance other than weak localization and the chiral magnetic anomaly.

Figure 1

Magnetoresistance of single-crystalline DyPdBi measured as a function of magnetic field strength in temperature range from 10 K to 300 K in (a) longitudinal and (b) transverse configuration of electrical current and magnetic field. Inset to panel (a) shows schematically the configuration of measurements.

Figure 2

(a) Angular dependence of the electrical resistivity of single-crystalline DyPdBi measured with $j\parallel a$-axis at several different temperatures in $B=14\mathrm{T}$. Red lines correspond to the fits with Eq. (2). (b) AMR isotherms derived from data shown in panel (a).

Figure 3

(a) Angular dependence of the planar Hall effect measured for single-crystalline DyPdBi at $T=10\mathrm{K}$ in several constant magnetic fields. The measurement geometry is shown in the inset. (b) Angular dependence of PHE in single-crystalline DyPdBi measured as in panel (a) in constant magnetic field $B=14\mathrm{T}$ at several different temperatures. Red solid lines in both (a) and (b) represent the fits of the function ${\rho }_{xy}=\mathrm{\Delta }\rho sin\left(\phi \right)cos\left(\phi \right)$. (c) Field dependence of $\mathrm{\Delta }\rho$ resistivity anisotropy of DyBdBi obtained from the fits shown in panel (a). (d) Hall resistivity of single-crystalline DyPdBi measured as a function of magnetic field direction at $T=10\mathrm{K}$ and in $B=14\mathrm{T}$. The measurement geometry is shown in the inset.

Figure 4

(a) Hall resistivity of single-crystalline DyPdBi measured as a function of magnetic field at several different temperatures with the experimental geometry displayed in Fig. 3. Inset shows the temperature dependence of the Hall coefficient at $T=10\mathrm{K}$. (b) Comparison of temperature dependence of the Hall coefficient $R_H$, and that of $\mathrm{\Delta }\rho \left(T\right)$ parameter of PHE, both determined in magnetic field of 14 T.

Figure 5

Resistivity measured at $T=10\mathrm{K}$, in transverse and longitudinal fields, with the spin-disorder (de Gennes-Friedel) resistivity subtracted. Dashed lines represent the fits with Eqs. (5) and (6).