Triple-Q state in magnetic breathing kagome lattice

TL;DR

This paper investigates the magnetic frustration and complex multi-Q states in a breathing kagome lattice formed by Mn monolayers, revealing topological spin textures and flat band effects with potential for nonlinear Hall phenomena.

Contribution

It introduces the magnetic breathing kagome lattice as a platform for realizing triple-Q states with topological charge, expanding understanding of frustrated magnetism and emergent topological effects.

Findings

Identification of a triple-Q state with nonzero topological charge

Discovery of flat band properties leading to complex spin configurations

Potential for nonlinear Hall effects due to topological spin textures

Abstract

Magnetic frustration in two-dimensional spin lattices with triangular motifs underpins a series of exotic states, ranging from multi-Q configurations to disordered spin-glasses. The antiferromagnetic kagome lattice, characterized by its network of corner-sharing triangles, represents a paradigmatic frustrated system exhibiting macroscopic degeneracy. Expanding upon the kagomerization mechanism, we focus on the magnetic breathing kagome lattice formed by a Mn monolayer deposited on a heavy metal substrate and capped with h-BN. The Mn kagome arrangement induces pronounced magnetic frustration, as evidenced by the nearly flat bands derived from spin spiral energy calculations. Including further-neighbor interactions reveals a spin spiral energy minimum along the $\Gamma$-K line and an intriguing triple-Q state with nonzero topological charge, potentially leading to highly nonlinear Hall effects. Furthermore, the flat band properties can further give rise to an even more complex spin configuration, marked by several Q-pockets in the spin structure factor. These results present a fertile ground for advancing the study of multi-Q states and exploring emergent topological phenomena.