Weyl Characteristics Induced an Anomalous Hall Effect in Double Half-Heusler Alloy Cr2FeCoAs2: A Density-Functional Study

Abstract

Magnetic Weyl semimetals can exhibit a significant electronic transport behavior known as the anomalous Hall effect caused by the inherent Berry curvature generated by Weyl fermions. This study presents the result of density-functional theory analysis focusing on the magnetic ground state, electronic properties, topological Weyl properties, nontrivial surface state, and anomalous Hall effect of the double half-Heusler compound Cr₂FeCoAs₂. We determined that Cr₂FeCoAs₂ acts as a ferrimagnetic half-metal with a total spin magnetic moment of 6 μ_B per unit cell. This system is particularly interesting as it features one insulating and one metallic topological channel. The minority-spin insulating channel shows an energy band gap of 1.26 eV. The majority spin channel consists of several sets of low-energy Weyl points. Among them, four exactly lie at the Fermi level. The chiral Weyl nodes, breaking time-reversal symmetry and protected by mirror symmetry, act as the monopole source and sink of the Berry curvature and provide a large intrinsic anomalous Hall conductivity approaching −190 Ω^–1 cm^–1 at the Fermi level and −370 Ω^–1 cm^–1 at 170 meV, which is comparable to those of topological magnetic materials. Additionally, nontrivial surface states are clearly present in Cr₂FeCoAs₂. Our work will support future experimental investigations into the previously unexplored topological phenomena of Cr₂FeCoAs₂.