Strain-induced half-metallic ferromagnetism and large anomalous Hall effect in Fe₂CrGe

Magnetic topological semimetals (TSMs) with broken time-reversal symmetry have recently attracted significant attention in condensed matter physics due to their fascinating topological properties. In this work, we present a comprehensive study of the intricate interplay between magnetism and topology in the full-Heusler compound Fe₂CrGe, based on density functional theory calculations. Our results demonstrate that the ground state of Fe₂CrGe is an antiferromagnetic (AFM) metal, which can be driven into a half-metallic ferromagnetic (HMF) phase through the application of uniaxial strain. Remarkably, both compressive and tensile strains of up to 3% preserve the robustness of the half-metallic character, underscoring its potential for strain-engineered spintronic applications. Monte Carlo simulations based on the Ising model are used to predict the Curie temperature of the ferromagnetic phase. Furthermore, a careful analysis of the band topology of the strained system revealed the existence of gapped nodal lines and symmetry-protected Weyl points (WPs) near the Fermi level in the presence of spin-orbit coupling (SOC) and finite magnetization. The simultaneous existence of gapped nodal lines and symmetry-protected WPs gives rise to a strong Berry curvature (BC) distribution, which in turn generates significant intrinsic anomalous Hall conductivity (AHC). The strain-induced HMF nature and non-zero AHC make the Heusler alloy Fe₂CrGe a promising contender for topological spintronics device applications and it can also be used as a strain-controlled Hall-switch.