Emergence of Meron Kekul\'e lattices in twisted N\'eel antiferromagnets

Abstract

A Kekul\'e lattice is an exotic, distorted lattice structure exhibiting alternating bond lengths, distinguished from naturally formed atomic crystals. Despite its evident applicability, the formation of a Kekul\'e lattice from topological solitons in magnetic systems has remained elusive. Here, we propose twisted bilayer easy-plane N\'eel antiferromagnets as a promising platform for achieving a "Meron Kekul\'e lattice"--a distorted topological soliton lattice comprised of antiferromagnetic merons as its lattice elements. We demonstrate that the cores of these merons are stabilized into the Kekul\'e-O pattern with different intracell and intercell bond lengths across moir\'e supercells, thereby forming a Meron Kekul\'e lattice. Moreover, the two bond lengths of the Meron Kekul\'e lattice can be fine-tuned by adjusting the twist angle and specifics of the interlayer exchange coupling, suggesting extensive control over the meron lattice configuration in contrast to conventional magnetic systems. These discoveries pave the way for exploring topological solitons with distinctive Kekul\'e attributes.