Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China , Chengdu 610054, China.
Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China.
Nano Lett. 2016 Mar 9;16(3):2072-5. doi: 10.1021/acs.nanolett.6b00110. Epub 2016 Feb 15.
We predict theoretical existence of intrinsic two-dimensional organic topological insulator (OTI) states in Cu-dicyanoanthracene (DCA) lattice, a system that has also been grown experimentally on Cu substrate, based on first-principle density functional theory calculations. The pz-orbital Kagome bands having a Dirac point lying exactly at the Fermi level are found in the freestanding Cu-DCA lattice. The tight-binding model analysis, the calculated Chern numbers, and the semi-infinite Dirac edge states within the spin-orbit coupling gaps all confirm its intrinsic topological properties. The intrinsic TI states are found to originate from a proper number of electrons filling of the hybridized bands from Cu atomic and DCA molecular orbitals based on which similar lattices containing noble metal atoms (Au and Cu) and those molecules with two CN groups (DCA and cyanogens) are all predicted to be intrinsic OTIs.
我们基于第一性原理密度泛函理论计算，预测了在 Cu-二氰基蒽（DCA）晶格中存在内在二维有机拓扑绝缘体（OTI）态的理论可能性，该系统也已在 Cu 衬底上进行了实验生长。在自由-standing Cu-DCA 晶格中发现了具有位于费米能级处的狄拉克点的 pz-轨道 Kagome 带。紧束缚模型分析、计算的陈数以及自旋轨道耦合间隙内的半无限狄拉克边缘态都证实了其内在的拓扑性质。基于从 Cu 原子和 DCA 分子轨道杂化带填充适当数量的电子，我们发现了内在 TI 态，这表明基于类似晶格的含有贵金属原子（Au 和 Cu）和具有两个 CN 基团的分子（DCA 和氰基）都可能是内在的 OTI。
