Strain induced half-metallic ferromagnetism and large anomalous Hall effect in Fe 2 CrGe

Abstract

The fascinating topological features of magnetic topological semimetals (TSMs) with broken time-reversal symmetry have attracted a lot of interest in condensed matter physics in recent years. The inherent complexity of magnetism, however, causes the research of magnetic topological phases to lag behind. In this manuscript, we report a thorough investigation of the interplay between magnetism and topology of the full Heusler compound Fe 2 CrGe, employing density functional theory calculations. The ground state of Fe 2 CrGe is in an antiferromagnetic (AFM) metallic state, which, upon applying uniaxial strain, undergoes a magnetic phase transition to a half-metallic ferromagnet (HMF) state. Both compressive and tensile strains have been applied up to 3%, and the robustness of the half-metallic nature has been observed. The Curie temperature of the FM state is estimated by Monte Carlo simulations of the Ising model. We also analyzed the band topology of the strained system and have identified gapped nodal lines and symmetry-protected Weyl points (WPs) close to E F 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 Fe 2 CrGe a promising contender for topological spintronics device applications and can also be used as a strain-controlled Hall-switch.