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

The presence of topological flat minibands in moire materials provides an opportunity to explore the interplay between topology and correlation. In this work, we study moire minibands in topological insulator films with two hybridized surface states under a moire superlattice potential created by two-dimensional insulating materials. We show the lowest conduction (highest valence) Kramers' pair of minibands can be Z 2 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\mathbb{Z}}}_{2}$$\end{document} non-trivial when the minima (maxima) of moire 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 moire heterostructure as a potential platform for studying interacting topological phases. Moire patterns have been experimentally observed in heterostructures comprised of topological insulator films. Here, the authors propose that topological insulator-based moire heterostructures could be a host of isolated topologically non-trivial moire minibands for the study of the interplay between topology and correlation.