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

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 moire superlattice arises. Several works explored the optical, electric, and electromechanical moire-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 moire 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.

Automated summary

In this study, tapping mode atomic force microscopy phase-imaging was used to directly visualize and quantify the spatial modulation of van der Waals (vdW) interlayer interactions in twisted layered materials. The results showed that a moire superlattice in the phase channel was observed only when noncontact forces were probed, indicating the modulation of vdW potential at the sample surface. The ability to modulate the vdW potential at the interface by layer twisting could be used for local adhesion engineering and surface functionalization.