Though Weyl fermions have recently been observed in several materials with broken inversion symmetry, there are very few examples of such systems with broken time reversal symmetry. Various ${\mathrm{Co}}_2$-based half-metallic ferromagnetic Heusler compounds are lately predicted to host Weyl-type excitations in their band structure. These magnetic Heusler compounds with broken time reversal symmetry are expected to show a large momentum space Berry curvature, which introduces several exotic magnetotransport properties. In this paper, we present a systematic analysis of experimental results on the anomalous Hall effect (AHE) in ${\mathrm{Co}}_2\mathrm{Ti}X$ ($X=\mathrm{Si}$ and Ge). This study is an attempt to understand the role of Berry curvature on AHE in the ${\mathrm{Co}}_2\mathrm{Ti}X$ family of materials. Anomalous Hall resistivity is observed to scale quadratically with longitudinal resistivity for both compounds. The detailed analysis indicates that in anomalous Hall conductivity, the intrinsic Karplus-Luttinger Berry phase mechanism dominates over the extrinsic skew scattering and side-jump mechanism.

• Received 10 March 2020
• Revised 29 July 2020
• Accepted 11 August 2020

DOI:https://doi.org/10.1103/PhysRevB.102.085147