<i>A</i>‑Site and Epitaxial Strain Effect on the Properties of <i>A</i>Mn<sub>3</sub>Sb<sub>5</sub> (<i>A</i> = K, Cs, and Rb) Kagome Lattices.

Abstract

Kagome lattices are an exciting family of compounds where frustrated magnetism, superconductivity, charge density wave (CDW) orders, topological features, large anomalous Hall conductivity, flat bands, and van Hove singularities collide. With this in mind, we theoretically studied the Mn-based Kagome <i>A</i>Mn₃Sb₅ (<i>A</i> = K, Rb, and Cs) lattices and explored the <i>A</i>-site's influence, as well as the epitaxial <i>xy</i>-strain effect on the structural, magnetic, and electronic properties. Through theoretical analysis, coupled with first-principles density functional theory calculations, we demonstrate that the entire family is dynamically stable, locking the ferromagnetic order as the ground-state configuration in the primitive cell and preventing charge-density wave condensation, as observed in the <i>A</i>V₃Sb₅ family. In these compounds, our results suggest an out-of-plane ferromagnetic response that, in turn, breaks the T -symmetry, allowing a nonzero Berry curvature. The latter leads to a symmetry-allowed anomalous Hall conductivity (σ _<i>αβ</i> ) as large as σ _<i>xy</i> = 402 S·cm^-1 in the CsMn₃Sb₅ and σ _<i>xy</i> = 442 S·cm^-1 under +3% in-plane epitaxial strain.