Physics Department - Beyond Conventional Moiré Physics: Emergent Structures and Topology

Abstract
Recent advances in moiré materials have revealed that twisted multilayer systems provide a versatile platform for engineering electronic structures and emergent quantum phenomena through geometry alone. Beyond the extensively studied flat-band physics in simple bilayer moiré systems, more complex multilayer and anisotropic structures have recently opened qualitatively new directions in moiré quantum matter.
In this talk, I will discuss several recent developments in theoretical studies of moiré systems beyond conventional periodic moiré superlattices. First, I will present the concept of “moire-of-moire” structures that emerge in twisted multilayer systems containing multiple competing moiré patterns. Their interference generates spontaneous domain formation and long-scale emergent structures, leading to novel electronic states and topological channels.
I will then discuss one-dimensional moiré physics realized in anisotropic twisted materials and graphene nanoribbon heterostructures. In these systems, lattice relaxation induces quasi-one-dimensional electronic structures and localized states associated with domain walls and emergent moiré potentials.
Finally, I will discuss interaction-driven topological phases in moiré systems with degenerate bands, focusing on recent theoretical proposals of non-Abelian topological states characterized by SU(2) Berry geometry and unconventional Chern structures. These studies suggest that moiré materials provide a promising platform for exploring quantum states beyond the conventional Abelian framework.