Magnetism, lattice dynamics, and anomalous Hall conductivity in kagome metal KMn₃Sb₅

Kagome metals are reported to exhibit remarkable properties, including superconductivity, charge density wave order, and a large anomalous Hall conductivity (AHC), which facilitate the implementation of spintronic devices. In this work, we theoretically study a novel kagome metal based on Mn magnetic sites in a KMn₃Sb₅ stoichiometry. By means of first-principles density functional theory calculations, we demonstrate that the studied compound is dynamically stable, locking the ferromagnetic order as the ground state configuration, thus preventing the charge-density-wave state as reported in its vanadium-based counterpart KV₃Sb₅. Our calculations reveal that KMn₃Sb₅ exhibits an out-of-plane (001) ferromagnetic response as the ground state, allowing for the emergence of topologically protected Weyl nodes near the Fermi level and nonzero AHC in this centrosymmetric system. We obtain a tangible AHC σ_xy = 314 S·cm⁻¹ component, which is comparable to that of other kagome metals. Finally, we explore the effect of the on-site Coulomb repulsion (+U) on the structural and electronic properties and find that, although the lattice parameters and σ_xy moderately vary with increasing +U, KMn₃Sb₅ stands as an ideal stable ferromagnetic kagome metal with a large AHC response.