Moiré Modulation of Van Der Waals Potential in Twisted Hexagonal Boron Nitride

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.

Keywords: atomic force microscopy; hexagonal boron nitride; layered materials; mechanical phase imaging; moiré superlattices; van der Waals interactions.