论文标题
2D共价有机框架中混合尺寸的孤立平坦带和物理
Isolated Flat Bands and Physics of Mixed Dimensions in a 2D Covalent Organic Framework
论文作者
论文摘要
我们证明，可以合理地将孤立的平坦带和零尺寸（0D），一个维度（1D）和两个维度（2D）（2D）的物理学合理地合并到单个2D材料中。这种独特的电子特性存在于最近合成的2D共价有机框架（COF）中，其中“ I”形的构建块和“ T”形连接器会导致准-0D桥单元连接的准1D链，该链被排列在稳定的2D lattice中。最低的空置传导带是一个孤立的平坦带，电子掺杂产生了新型的量子现象，例如磁力和莫特绝缘阶段。最高的占据价频带来自准1D链中的波函数。在该系统中说明了混合尺寸物理的示例。这种材料中强的电子孔不对称会导致较大的锯齿系数，而链的准1D性质则导致线性二色性，并结合强大的2D激子。我们阐明了设计和优化2D COF的策略，以容纳孤立的平坦频带和量子限制的1D子系统。这里讨论的2D COF的特性提供了这个开放研究领域中有趣的可能性。
We demonstrate that it is possible to rationally incorporate both an isolated flat band, and the physics of zero dimensions (0D), one dimension (1D), and two dimensions (2D) in a single 2D material. Such unique electronic properties are present in a recently synthesized 2D covalent organic framework (COF), where "I"-shaped building blocks and "T"-shaped connectors result in quasi-1D chains that are linked by quasi-0D bridge units arranged in a stable 2D lattice. The lowest unoccupied conduction band is an isolated flat band, and electron-doping gives rise to novel quantum phenomena, such as magnetism and Mott insulating phases. The highest occupied valence band arises from wave functions in the quasi-1D chains. Examples of mixed dimensional physics are illustrated in this system. The strong electron-hole asymmetry in this material results in a large Seebeck coefficient, while the quasi-1D nature of the chains leads to linear dichroism, in conjunction with strongly bound 2D excitons. We elucidate strategies to design and optimize 2D COFs to host both isolated flat bands and quantum-confined 1D subsystems. The properties of the 2D COF discussed here provide a taste of the intriguing possibilities in this open research field.
