Chiodini Stefano, Kerfoot James, Venturi Giacomo, Mignuzzi Sandro, Alexeev Evgeny M, Teixeira Rosa Bárbara, Tongay Sefaattin, Taniguchi Takashi, Watanabe Kenji, Ferrari Andrea C, Ambrosio Antonio
Center for Nano Science and Technology, Fondazione Istituto Italiano di Tecnologia, Via G. Pascoli 70, Milan 20133, Italy.
Cambridge Graphene Centre, University of Cambridge, 9, JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom.
ACS Nano. 2022 May 24;16(5):7589-7604. doi: 10.1021/acsnano.1c11107. Epub 2022 Apr 29.
When a twist angle is applied between two layered materials (LMs), the registry of the layers and the associated change in their functional properties are spatially modulated, and a moiré superlattice arises. Several works explored the optical, electric, and electromechanical moiré-dependent properties of such twisted LMs but, to the best of our knowledge, no direct visualization and quantification of van der Waals (vdW) interlayer interactions has been presented, so far. Here, we use tapping mode atomic force microscopy phase-imaging to probe the spatial modulation of the vdW potential in twisted hexagonal boron nitride. We find a moiré superlattice in the phase channel only when noncontact (long-range) forces are probed, revealing the modulation of the vdW potential at the sample surface, following AB and BA stacking domains. The creation of scalable electrostatic domains, modulating the vdW potential at the interface with the environment by means of layer twisting, could be used for local adhesion engineering and surface functionalization by affecting the deposition of molecules or nanoparticles.
当在两个层状材料(LM)之间施加扭转角时,层的配准及其功能特性的相关变化会在空间上受到调制,从而产生莫尔超晶格。一些研究探讨了此类扭曲层状材料的光学、电学和机电莫尔相关特性,但据我们所知,到目前为止,尚未有对范德华(vdW)层间相互作用的直接可视化和量化报道。在这里,我们使用轻敲模式原子力显微镜相位成像来探测扭曲六方氮化硼中vdW势的空间调制。我们发现,只有在探测非接触(长程)力时,相位通道中才会出现莫尔超晶格,这揭示了样品表面vdW势的调制情况,遵循AB和BA堆叠域。通过层扭转在与环境的界面处调制vdW势来创建可扩展的静电域,可用于通过影响分子或纳米颗粒的沉积进行局部粘附工程和表面功能化。