Kong Xiangru, Li Linyang, Peeters François M
International Center for Quantum Materials and School of Physics, Peking University, 100871 Beijing, People's Republic of China.
J Phys Condens Matter. 2019 Jun 26;31(25):255302. doi: 10.1088/1361-648X/ab132f. Epub 2019 Mar 25.
In van der Waals heterostructures consisting of graphene and a substrate, lattice mismatch often leads to a moiré pattern with a huge supercell, preventing its treatment within first-principles calculations. Previous theoretical works considered mostly simple stacking models such as AB, AA with straining the lattice of graphene to match that of the substrate. Here, we propose a moiré superlattice build from graphene and porous graphene or graphyne like monolayers, having a lower interlayer binding energy, needing little strain in order to match the lattices. In contrast to the results from the simple stacking models, the present ab initio calculations for the moiré superlattices show different properties in lattice structure, energy, and band structures. For example, the Dirac cone at the K point is preserved and a linear energy dispersion near the Fermi level is obtained.
在由石墨烯和衬底组成的范德华异质结构中，晶格失配常常导致具有巨大超胞的莫尔图案，这使得在第一性原理计算中难以对其进行处理。先前的理论工作大多考虑简单的堆叠模型，如AB、AA堆叠，并对石墨烯晶格施加应变以使其与衬底晶格匹配。在此，我们提出一种由石墨烯与多孔石墨烯或类石墨炔单层构建的莫尔超晶格，其具有较低的层间结合能，为匹配晶格几乎不需要应变。与简单堆叠模型的结果不同，目前对莫尔超晶格的从头算计算在晶格结构、能量和能带结构方面展现出不同的性质。例如，K点处的狄拉克锥得以保留，并且在费米能级附近获得了线性能量色散。
