Abstract：
The honeycomb lattice is a fundamental two-dimensional (2D) network that gives rise to surprisingly rich electronic properties. While its expansion to 2D supramolecular assembly is conceptually appealing, its realization is not straightforward because of weak intermolecular coupling and the strong influence of a supporting substrate. Here, we show that the application of a triptycene derivative with phenazine moieties, Trip-Phz, solves this problem due to its strong intermolecular π-π pancake bonding and nonplanar geometry. Our scanning tunneling microscopy (STM) measurements demonstrate that Trip-Phz molecules self-assemble on a Ag(111) surface to form chiral and commensurate honeycomb lattices. Electronically, the network can be viewed as a hybrid of honeycomb and kagome lattices. The Dirac and flat bands predicted by a simple tight-binding model are reproduced by total density functional theory (DFT) calculations, highlighting the protection of the molecular bands from the Ag(111) substrate. The present work offers a rational route for creating chiral 2D supramolecules that can simultaneously accommodate pristine Dirac and flat bands.
摘要：
蜂窝晶格是基本的二维(2D)网络,其产生令人惊讶的丰富电子特性。虽然它扩展到2D超分子组装在概念上很有吸引力，由于弱的分子间耦合和支撑衬底的强烈影响，其实现并不简单。这里,我们证明了具有吩嗪部分的三烯衍生物的应用，Trip-Phz,由于其强大的分子间π-π煎饼键合和非平面几何形状，解决了这个问题。我们的扫描隧道显微镜（STM）测量表明，Trip-Phz分子在Ag（111）表面上自组装，形成了手性和相称的蜂窝晶格。电子，该网络可以被视为蜂窝和kagome晶格的混合。通过总密度泛函理论（DFT）计算再现了由简单的紧密结合模型预测的狄拉克和平坦带，突出的保护分子带从Ag（111）衬底。目前的工作提供了一种合理的途径，用于创建可以同时容纳原始狄拉克和平坦带的手性2D超分子。
