Anomalous Hall effect and the role of Berry curvature in Co2TiSn Heusler films

Abstract

Various Co2-based Heusler compounds are predicted to be half-metallic ferromagnets with Weyl points. These systems with lack of time inversion symmetry possess a momentum space Berry curvature that can introduce exotic transport properties. The present study, on epitaxially grown Co2TiSn films, is an approach to understand and explore this possibility. The theoretical investigation shows that the Berry curvature is significant for the total anomalous Hall effect in experimentally grown Co2TiSn films. The deviation between the theory and experiment is due to the influence of side jump and skew scattering mechanisms. From a theoretical point of view, the intrinsic contribution to the anomalous Hall effect originates from partially gaped nodal lines due to the symmetry reduction induced by the lack of time reversal symmetry. Furthermore, from hard x-ray photoelectron spectroscopy measurements, we establish an electronic structure in the film that is comparable to the theoretical density of states calculations. These results provide intuitive insight into Heusler spintronics rooted in topological electronic structure.