Electronic correlations in two-dimensional materials play a crucial role in stabilising emergent phases of matter. The realisation of correlation-driven phenomena in graphene has remained a longstanding goal, primarily due to the absence of strong electron-electron interactions within its low-energy bands. In this context, magic-angle twisted bilayer graphene has recently emerged as a novel platform featuring correlated phases favoured by the low-energy flat bands of the underlying moiré superlattice. Notably, the observation of correlated insulators and superconductivity, and the interplay between these phases have garnered significant attention. A wealth of correlated phases with unprecedented tunability was discovered subsequently, including orbital ferromagnetism, Chern insulators, strange metallicity, density waves, and nematicity. However, a comprehensive understanding of these closely competing phases remains elusive. The ability to controllably twist and stack multiple graphene layers has enabled the creation of a whole new family of moiré superlattices with myriad properties. Here, we review the progress and development achieved so far, encompassing the rich phase diagrams offered by these graphene-based moiré systems. Additionally, we discuss multiple phases recently observed in non-moiré multilayer graphene systems. Finally, we outline future opportunities and challenges for the exploration of hidden phases in this new generation of moiré materials.

中文翻译：

---

石墨烯平带中的涌现相


二维材料中的电子相关性在稳定物质涌现相方面发挥着至关重要的作用。在石墨烯中实现相关驱动现象仍然是一个长期目标，这主要是由于其低能带内缺乏强电子-电子相互作用。在这种背景下，魔角扭曲双层石墨烯最近作为一种新颖的平台出现，其特征是受到底层莫尔超晶格的低能平带的青睐。值得注意的是，相关绝缘体和超导性的观察以及这些相之间的相互作用引起了人们的广泛关注。随后发现了大量具有前所未有的可调谐性的相关相，包括轨道铁磁性、陈绝缘体、奇异金属性、密度波和向列性。然而，对这些紧密竞争的阶段的全面理解仍然难以实现。可控扭曲和堆叠多个石墨烯层的能力使得能够创建具有多种特性的全新莫尔超晶格系列。在这里，我们回顾了迄今为止所取得的进展和发展，包括这些基于石墨烯的莫尔系统提供的丰富的相图。此外，我们还讨论了最近在非莫尔多层石墨烯系统中观察到的多个相。最后，我们概述了探索新一代莫尔材料中隐藏相的未来机遇和挑战。