Anđelković Miša, Milovanović Slaviša P, Covaci Lucian, Peeters François M
Departement Fysica , Universiteit Antwerpen , Groenenborgerlaan 171 , B-2020 Antwerpen , Belgium.
Nano Lett. 2020 Feb 12;20(2):979-988. doi: 10.1021/acs.nanolett.9b04058. Epub 2020 Jan 28.
A periodic spatial modulation, as created by a moiré pattern, has been extensively studied with the view to engineer and tune the properties of graphene. Graphene encapsulated by hexagonal boron nitride (hBN) when slightly misaligned with the top and bottom hBN layers experiences two interfering moiré patterns, resulting in a so-called supermoiré (SM). This leads to a lattice and electronic spectrum reconstruction. A geometrical construction of the nonrelaxed SM patterns allows us to indicate qualitatively the induced changes in the electronic properties and to locate the SM features in the density of states and in the conductivity. To emphasize the effect of lattice relaxation, we report band gaps at all Dirac-like points in the hole doped part of the reconstructed spectrum, which are expected to be enhanced when including interaction effects. Our result is able to distinguish effects due to lattice relaxation and due to the interfering SM and provides a clear picture on the origin of recently experimentally observed effects in such trilayer heterostuctures.
一种由莫尔条纹产生的周期性空间调制，已被广泛研究，旨在设计和调控石墨烯的性质。当由六方氮化硼（hBN）封装的石墨烯与顶部和底部hBN层稍有不对齐时，会经历两种相互干涉的莫尔条纹，从而产生所谓的超莫尔条纹（SM）。这会导致晶格和电子能谱重构。对未弛豫的SM图案进行几何构造，使我们能够定性地指出电子性质的诱导变化，并在态密度和电导率中定位SM特征。为了强调晶格弛豫的影响，我们报告了重构谱空穴掺杂部分所有类狄拉克点处的带隙，预计在考虑相互作用效应时这些带隙会增大。我们的结果能够区分晶格弛豫和干涉SM所产生的效应，并为最近在此类三层异质结构中实验观察到的效应的起源提供清晰的图景。
