Robust half-metallicity and topological properties in square-net potassium manganese chalcogenides

Using combination of first-principles and model Hamiltonian approaches, we investigate the electronic, magnetic, and topological properties of potassium manganese chalcogenides that host square nets of Mn and chalcogen atoms. Our analysis establishes these compounds to be robust half-metallic ferromagnets

with ferromagnetism arising from a kinetic energy-driven double-exchange mechanism. The presence of finite spin-orbit coupling at chalcogen sites triggers nontrivial topology of the electronic structure close to the Fermi level. This puts the studied compounds in the class of topological half-metals with appreciable values of anomalous Hall conductivity, opening up the application possibility in topological quantum spintronics. Cleavability of these layered compounds makes the situation further promising.