Since the discovery of graphene, two-dimensional materials with atomic level thickness have rapidly grown to be a prosperous field of physical science with interdisciplinary interest for their fascinating properties and broad applications. Very recently, the experimental observation of ferromagnetism in a Cr2Ge2Te6 bilayer and a CrI3 monolayer opened a door to pursue long-absent intrinsic magnetic orders in two-dimensional materials. Meanwhile, the ferroelectricity was also experimentally found in a SnTe monolayer and CuInP2S6 few layers. The emergence of these ferroic orders in the two-dimensional limit not only brings new challenges to our physical knowledge but also provides more functionalities for potential applications. Among various two-dimensional ferroic ordered materials, transition/rare-earth metal halides and their derivants are very common. In this Research Update, based on transition/rare-earth metal halides, the physics of various ferroic orders in two-dimensional materials will be illustrated. The potential applications based on their magnetic and polar properties will also be discussed.

中文翻译：

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二维过渡/稀土金属卤化物中的铁质订单

自从发现石墨烯以来，具有原子级厚度的二维材料因其迷人的特性和广泛的应用而迅速发展成为具有跨学科兴趣的物理科学领域。最近，对 Cr2Ge2Te6 双层和 CrI3 单层中铁磁性的实验观察为探索二维材料中长期缺失的本征磁序打开了大门。同时，铁电性也在 SnTe 单层和 CuInP2S6 几层中被实验发现。这些在二维极限中出现的铁质有序不仅给我们的物理知识带来了新的挑战，而且为潜在的应用提供了更多的功能。在各种二维铁性有序材料中，过渡金属/稀土金属卤化物及其衍生物非常常见。在本研究更新中，基于过渡金属/稀土金属卤化物，将说明二维材料中各种铁质级的物理特性。还将讨论基于其磁性和极性特性的潜在应用。