Nodal-line and triple point fermion induced anomalous Hall effect in the topological Heusler compound Co2CrGa

Magnetic topological semimetals have interesting anomalous behavior and can be manipulated by tuning the symmetry-protected nodal crossings. Co2-based full Heusler compounds serve as a fertile playground where various novel topological properties can be investigated. In this paper, we present a systematic investigation of the anomalous Hall effect (AHE) in the ferromagnetic Heusler compound Co2CrGa using combined experimental and theoretical studies. The anomalous Hall resistivity pY is observed to scale nearly quadratically with the longitudinal resistivity pee, and further experimental analysis suggests that the AHE in Co2CrGa should be dominated by the intrinsic Karplus-Luttinger Berry phase mechanism. Experimental results also reveal that the anomalous Hall conductivity (AHC) is as large as -569 S/cm at 10 K with an intrinsic contribution of <^>526 S/cm and the observed AHC is nearly temperature independent. In addition to the large AHC, we also found an exceptionally large anomalous Hall angle of -8.5% and a large anomalous Hall factor of -0.23 V-1 simultaneously at room temperature. First-principles calculations suggest that the Berry curvature originates from a gapped nodal line and that Weyl nodes which are generated from the triple point near the Fermi level EF in the presence of spin-orbit coupling are responsible for the observed large AHC in this compound.