Anomalous Hall effect in topological Weyl and nodal-line semimetal Heusler compound Co₂VAl

Magnetic topological semimetals (TSMs) with broken time-reversal symmetry are very rare and have drawn significant attention in condensed matter physics due to their numerous intriguing topological properties. Among these various magnetic TSMs, Co₂-based full Heusler compounds are of current interest, since a few of these materials exhibit Weyl and nodal fermions in their topological band structure. In this work, we report a comprehensive study of anomalous Hall effect (AHE) in the ferromagnetic full Heusler compound Co₂VAl. Recent studies indicate that the intrinsic AHE is closely related to the Berry curvature of the occupied electronic Bloch states. The present study of Co₂VAl attempts to understand and explore the possibility of topology-induced AHE. The anomalous Hall resistivityρxyAis observed to scale quadratically with the longitudinal resistivityρ. Our experimental results also reveal that the anomalous Hall conductivity (AHC) is ∼85 cm^-1at 2 K with an intrinsic contribution of ∼75.6 S cm^-1, and is nearly insensitive to temperature. The first principle calculations note that the Berry curvature originated from a gapped nodal line and symmetry-protected Weyl nodes near the Fermi level (EF) is the main source of AHE in this compound. Thus, this investigation on Co₂VAl discloses that it is a ferromagnetic Weyl and nodal-line TSM. The theoretically calculated AHC is in well agreement with the experimentally obtained AHC.