Quantum anomalous Hall effect in twisted bilayer graphene

Recent advancements in two-dimensional van der Waals moiré materials have unveiled the captivating landscape of moiré physics. In twisted bilayer graphene (TBG) at ‘magic angles’, strong electronic correlations give rise to a diverse array of exotic physical phenomena, including correlated insulating states, superconductivity, magnetism, topological phases, and the quantum anomalous Hall (QAH) effect. Notably, the QAH effect demonstrates substantial promise for applications in electronic and quantum computing devices with low power consumption. This article focuses on the latest developments surrounding the QAH effect in magic-angle TBG. It provides a comprehensive analysis of magnetism and topology — two crucial factors in engineering the QAH effect within magic-angle TBG. Additionally, it offers a detailed overview of the experimental realization of the QAH effect in moiré superlattices. Furthermore, this review highlights the underlying mechanisms driving these exotic phases in moiré materials, contributing to a deeper understanding of strongly interacting quantum systems and facilitating the manipulation of new material properties to achieve novel quantum states.