First-principles Methodology for studying magnetotransport in magnetic materials

Unusual magnetotransport behaviors such as temperature dependent negative magnetoresistance(MR) and bowtie-shaped MR have puzzled us for a long time. Although several mechanisms have been proposed to explain them, the absence of comprehensive quantitative calculations has made these explanations less convincing. In our work, we introduce a methodology to study the magnetotransport behaviors in magnetic materials. This approach integrates anomalous Hall conductivity induced by Berry curvature, with a multi-band ordinary conductivity tensor, employing a combination of first-principles calculations and semi-classical Boltzmann transport theory. Our method incorporates both the temperature dependency of relaxation time and anomalous Hall conductivity, as well as the field dependency of anomalous Hall conductivity. We initially test this approach on two-band models and then apply it to a Weyl semimetal . The results, which align well with experimental observations in terms of magnetic field and temperature dependencies, demonstrate the efficacy of our approach. Additionally, we have investigated the distinct behaviors of magnetoresistance (MR) and Hall resistivities across various types of magnetic materials. This methodology provides a comprehensive and efficient means to understand the underlying mechanisms of the unusual behaviors observed in magneto-transport measurements in magnetic materials.