Tuesday 04 March 2025
Researchers have made a significant breakthrough in understanding the behavior of semimetals, a class of materials that exhibit properties of both metals and insulators. By studying the planar-Hall response of these materials, scientists have gained insight into the intricate relationships between topology, magnetism, and electrical conductivity.
Semimetals are characterized by a unique property known as topological protection, which allows them to maintain their electronic structure even in the presence of defects or impurities. This protection is due to the existence of topologically nontrivial band structures, where energy bands intersect at specific points called nodal points.
The planar-Hall response is a phenomenon that occurs when an electric current flows through a material in the presence of a magnetic field. In semimetals, this response is particularly interesting because it reveals the interplay between topology and magnetism. By analyzing the planar-Hall response, researchers can gain insight into the behavior of topological electrons, which are particles that exhibit unique properties due to their relationship with the material’s band structure.
In recent studies, scientists have used numerical simulations to explore the planar-Hall response of semimetals carrying pseudospin-1 quantum numbers. These materials exhibit triple-fold degeneracy at nodal points, a property that has been linked to the presence of topological fermions.
The researchers found that the planar-Hall response is sensitive to the Berry curvature and orbital magnetic moment, which are two fundamental properties that arise from the material’s band structure. The Berry curvature is a measure of how the electronic states change as an electron moves through the material, while the orbital magnetic moment arises from the interaction between electrons and the magnetic field.
The simulations revealed that the planar-Hall response can be decomposed into two contributions: one arising from the anomalous Hall effect, which is a classical phenomenon that occurs when electrons move in the presence of a magnetic field, and another contribution from the Lorentz-force part, which is a quantum mechanical effect that arises from the interaction between electrons and the magnetic field.
These findings have important implications for our understanding of topological semimetals. By studying the planar-Hall response, researchers can gain insight into the behavior of topological electrons and their relationship with magnetism. This knowledge can be used to design new materials with unique properties, such as high-temperature superconductors or topological insulators.
Cite this article: “Unraveling the Interplay between Topology and Magnetism in Semimetals”, The Science Archive, 2025.
Semimetals, Planar-Hall Response, Topology, Magnetism, Electrical Conductivity, Topological Protection, Nodal Points, Berry Curvature, Orbital Magnetic Moment, Anomalous Hall Effect
