Tunable anomalous Hall and Nernst effects in magnetic Weyl semimetalsCo2-xCrxMnGe

The discovery of magnetic Weyl semimetals (WSMs) has drawn significant interest due to their exceptional topological properties and anomalous transport behaviors, presenting exciting possibilities for advanced technological applications. Co-based Heusler compounds, with their unique band structures, have emerged as key materials for exploring the interplay between magnetism and topology. In this work, we perform a detailed first-principles study on Co2-xCr_xMnGe Heusler alloys (0⩽x⩽1), proposing new candidates with significantly enhanced nontrivial transport properties. Multiple Weyl points (WPs) have been observed intrinsically in ferromagnetic Heulser alloy Co₂MnGe, and the presence of bulk WPs is confirmed by the presence of isolated Fermi arcs and surface states. A significant Berry curvature is observed that arises from symmetry-protected WPs and gaped nodal lines and drives towards fascinating transport behavior. Our results show that Cr doping not only modifies the crystal symmetry but also enhances the Berry curvature, leading to a substantial effect in anomalous Hall conductivity (AHC). Notably, comparable intrinsic AHC values are observed over a range of Cr concentrations (x= 0, 0.25, and 0.5) and thus demonstrate the effect of substitutional doping on topological properties as well as transport behaviors. Furthermore, we systematically explore the anomalous Nernst conductivity in these systems with Weyl fermions. These findings underscore the potential of substitutional doping to significantly enhance topological properties and anomalous transport behaviors, paving the way for the development of Co-based magnetic WSMs with superior performance in spintronic and electronic applications.