Pressure-controlled anomalous Hall conductivity in the half-Heusler antiferromagnet GdPtBi

Controlling the intrinsic anomalous Hall conductivity (AHC) induced by Berry curvature is of significance in potential applications. Half-Heusler antiferromagnet GdPtBi provides an excellent platform to design and control the AHC, owing to its simple band structure near the Fermi level. Here, we systematically study the pressure-dependent magnetotransport properties of GdPtBi, in which the AHC can be continuously tuned by applying hydrostatic pressure. While the band structure and magnetism of GdPtBi bear minor changes below 2 GPa, the AHC decreases progressively with increasing pressure, and eventually vanishes at $P=1.5\mathrm{GPa}$. The chiral anomaly effect and electronic structure calculations further manifest that the Weyl nodes persist in this pressure range under magnetic field. Further analysis indicates that the disappearance of AHC in GdPtBi originates from the shift of the Fermi level relative to the Weyl nodes or the change of the canted spin structure of Gd ions in finite magnetic field under pressure. Our results show that pressure is an effective way to tune the anomalous Hall effect in magnetic topological semimetals.

Figure 1

Temperature-dependent longitudinal resistivity ${\rho }_{xx}$ of GdPtBi at various hydrostatic pressures. Inset: Pressure dependence of antiferromagnetic transition temperature $T_{\mathrm{N}}$.

Figure 2

(a) Field-dependent transverse magnetoresistance (MR) of GdPtBi at $T=2\mathrm{K}$ under different pressures. It has been symmetrized with respect to positive and negative magnetic fields to remove the Hall contribution. Inset: MR in the magnetic field between 0 and 6 T at ambient pressure. The arrow indicates the anomaly exhibited in MR at about 2 T. (b) Field dependence of Hall resistivity ${\rho }_{xy}$ under varying pressures at $T=2\mathrm{K}$. The Hall data were antisymmetrized with respect to positive and negative magnetic fields to remove the ${\rho }_{xx}$ component. The arrow indicates the anomalous hump shown in ${\rho }_{xy}$ around 2 T. (c)–(e) Pressure-dependent carrier density $n_{\mathrm{h}}$, mobility ${\mu }_{\mathrm{h}}$, oscillation frequencies $F$, Fermi energy $E_{\mathrm{F}}$, Fermi velocity $v_{\mathrm{F}}$, and Fermi vector $k_{\mathrm{F}}$ at $T=2\mathrm{K}$.

Figure 3

(a) Field-dependent Hall conductivity ${\sigma }_{xy}$ under various pressures at 2 K. (b) Anomalous Hall conductivity (AHC) $\mathrm{\Delta }{\sigma }_{xy}$ as a function of the magnetic field under different pressures at 2 K. (c) Pressure dependence of $\mathrm{\Delta }{\sigma }_{xy}$ at 2 K. (d) Field-dependent longitudinal resistivity ($B$//$E$) under different pressures at 2 K.

Figure 4

(a)–(d) Calculated band structures at 0, 0.5, 1, and 2 GPa, respectively. (e) Band structure around the Γ point in a small energy window near the Fermi level. (f) The enlarged window of the hole band around the Γ point near the Fermi level.