  Moir\'e superlattices from stacks of van der Waals materials offer an
exciting arena in the fields of condensed matter physics and materials science.
Typically, these moir\'e superlattices consist of materials with identical or
similar structures, and the long moir\'e period arises from a small twist angle
or lattice mismatch. In this article, we discuss that long moir\'e period
appears in a new moir\'e system by stacking two dissimilar van der Waals layers
with large lattice mismatch, resulting in couplings between moir\'e bands from
remote valleys in the momentum space. In this system, the first layer is
reconstructed using a $\sqrt{3}$ by $\sqrt{3}$ supercell that resembles the
Kekul\'e distortion in graphene, and such reconstruction becomes nearly
commensurate with the second layer. This Kekul\'e moir\'e superlattice is
realized in heterostructures of transition metal dichalcogenides and metal
phosphorus trichalcogenides such as MoTe$_2$/MnPSe$_3$. By first-principles
calculations, we demonstrate that the antiferromagnetic MnPSe$_3$ strongly
couples the otherwise degenerate Kramers' valleys of MoTe$_2$, resulting in
valley pseudospin textures that depend on N\'eel vector direction, stacking
geometry, and external fields. With one hole per moir\'e supercell, we predict
that the system can become a Chern insulator, of which the topology is tunable
by external fields.

Mesoscale and Nanoscale Physics;Materials Science