Kagome KMn3Sb5 metal: Magnetism, lattice dynamics, and anomalous Hall conductivity

Kagome metals are reported to exhibit remarkable properties, including superconductivity, charge density wave order, and a large anomalous Hall conductivity, which facilitate the implementation of spintronic devices. In this work, we study a kagome metal based on Mn magnetic sites in a ${\mathrm{KMn}}₃{\mathrm{Sb}}₅$ 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 ${\mathrm{KV}}₃{\mathrm{Sb}}₅$. Our calculations predict that ${\mathrm{KMn}}₃{\mathrm{Sb}}₅$ 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 anomalous Hall conductivity (${\ensuremath{\sigma}}_{\ensuremath{\alpha}\ensuremath{\beta}}$) in this centrosymmetric system. We obtain a tangible ${\ensuremath{\sigma}}_xy=314\phantom{\rule{4pt}{0ex}}\mathrm{S}\phantom{\rule{0.16em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ 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. We observed a switching of the magnetic moment from the $z$ axis to the $x$ axis, for $U$ values larger than 1.0 eV. Thus, we find that, although the lattice parameters, magnetic moment, and ${\ensuremath{\sigma}}_{\ensuremath{\alpha}\ensuremath{\beta}}$ moderately vary with increasing $+U$, ${\mathrm{KMn}}₃{\mathrm{Sb}}₅$ stands as an ideal stable ferromagnetic kagome metal with a tangible anomalous Hall conductivity response.