Intrinsic and extrinsic anomalous transport properties in noncollinear antiferromagnetic Mn$_3$Sn from first-principle calculations

Abstract: Mn$_3$Sn has garnered significant attention due to its kagome lattice, 120$^\circ$ noncollinear antiferromagnetic order, and substantial anomalous Hall effect. In this study, we comprehensively explore intrinsic and extrinsic contributions to anomalous Hall, anomalous Nernst, and anomalous thermal Hall effects, employing first-principle calculations and group theory analysis. Comparative analysis between our theoretical results and available experimental data underscores the predominance of intrinsic mechanism in shaping anomalous transport properties at low temperatures. Specifically, Weyl fermions are identified as the primary contributors to intrinsic anomalous Hall conductivity. The significance of extrinsic mechanisms becomes evident at high temperatures, especially when the longitudinal charge conductivity falls into the dirty regime, where the side jump mechanism plays a vital role. Extrinsic contributions to anomalous transport properties are primarily influenced by the electronic states residing at the Fermi surfaces. Furthermore, anomalous transport properties exhibit periodic variations when subjected to spin rotations within the kagome plane, achievable by applying an external magnetic field. Our findings advance the understanding of anomalous transport phenomena in Mn$_3$Sn and offer insights into potential applications of noncollinear antiferromagnetic materials in spintronics and spin caloritronics.