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

Abstract 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 resistivity ρ x y A is observed to scale quadratically with the longitudinal resistivity ρ xx . Our experimental results also reveal that the anomalous Hall conductivity (AHC) is ∼85 cm−1 at 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 ( E F ) 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.