Topological minibands and interaction driven quantum anomalous Hall state in topological insulator based moiré heterostructures

TL;DR

This paper explores how moiré patterns in topological insulator materials can create unique electronic states for studying topology and electron interactions.

Contribution

The study identifies a new platform using topological insulator moiré heterostructures to realize interaction-driven quantum anomalous Hall states.

Findings

Topological flat minibands can form in moiré heterostructures with six-fold rotation symmetry.

Coulomb interactions can drive these minibands into a quantum anomalous Hall state when half-filled.

Monolayer Sb2 on Sb2Te3 films is proposed as a candidate for realizing these effects.

Abstract

The presence of topological flat minibands in moiré materials provides an opportunity to explore the interplay between topology and correlation. In this work, we study moiré minibands in topological insulator films with two hybridized surface states under a moiré superlattice potential created by two-dimensional insulating materials. We show the lowest conduction (highest valence) Kramers’ pair of minibands can be \documentclass[12pt]{minimal}
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\begin{document}$${{\mathbb{Z}}}_{2}$$\end{document}Z2 non-trivial when the minima (maxima) of moiré potential approximately form a hexagonal lattice with six-fold rotation symmetry. Coulomb interaction can drive the non-trivial Kramers’ minibands into the quantum anomalous Hall state when they are half-filled, which is further stabilized by applying external gate voltages to break inversion. We propose the monolayer Sb2 on top of Sb2Te3 films as a candidate based on first principles calculations. Our work demonstrates the topological insulator based moiré heterostructure as a potential platform for studying interacting topological phases.

Moiré patterns have been experimentally observed in heterostructures comprised of topological insulator films. Here, the authors propose that topological insulator-based moiré heterostructures could be a host of isolated topologically non-trivial moiré minibands for the study of the interplay between topology and correlation.

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