Kekulé Moiré Superlattices

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Chemistry

Background:

• Moiré superlattices are crucial for emergent phenomena in layered materials.
• Achieving long moiré periodicities from dissimilar layers with large lattice mismatches is challenging.
• Coupling of electronic states in remote momentum-space valleys is key for novel quantum properties.

Purpose of the Study:

• To propose and theoretically investigate a new moiré system with long periodicity from dissimilar van der Waals layers.
• To explore the potential of a reconstructed first layer (Kekulé distortion) to achieve near-commensurability with a second layer.
• To demonstrate the realization of tunable topological phases and valley pseudospin textures.

Main Methods:

• Utilizing first-principles calculations to model heterostructures like MoTe2/MnPSe3.
• Reconstructing the first layer using a supercell to mimic Kekulé distortion.
• Analyzing the coupling between moiré bands and valley properties.

Main Results:

• Demonstrated a novel Kekulé moiré superlattice enabling coupling between remote valleys.
• Showcased strong coupling between MoTe2 Kramers' valleys induced by antiferromagnetic MnPSe3.
• Observed valley pseudospin textures dependent on Néel vector, stacking, and external fields.

Conclusions:

• The proposed Kekulé moiré superlattice offers a new platform for exploring exotic electronic and topological properties.
• Heterostructures of transition metal dichalcogenides and metal phosphorus trichalcogenides are promising for realizing these systems.
• The system exhibits tunable Chern insulator phases with potential applications in spintronics and topological quantum computing.