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

Abstract

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.

Ultrafast Electronic Relaxation Dynamics of Atomically Thin MoS2 Is Accelerated by Wrinkling

“…Colored lines represent Pos(C N ,1 ) in the three regions with associated fitting error indicated by dashed rectangles. This can be used to derive N as − N = π 2 cos − 1 [ Pos false( normalC N , 1 false) / Pos false( normalC ∞ false) ] where Pos(C ∞ ) = 33.93 cm –1 is Pos(C N ,1 ) in bulk MoS 2 .…”

“…73 The latter provides the largest contribution to the total error, limiting the accuracy to ±0.06 cm −1 . 73 TR-PEEM Measurements. We use a high-repetition-rate, highpower Yb fiber laser (Tangerine 30, Amplitude Systemes), which delivers 40 μJ, 320 fs pulses at 0.6 MHz and a 1.03 μm center wavelength (1.20 eV photon energy).…”

“…Identification of N for N > 5 requires measurements of Pos­(C) with a precision that exceeds the spectral resolution of the system (typical shift of ∼0.1 cm –1 vs spectral resolution of ∼0.6 cm –1 ). However, peak position evaluation with subpixel accuracy can be achieved via spectral fitting . The accuracy is determined by fitting error, statistical errors arising from spatial variation, CCD noise, and errors associated with the registry of pixels relative to the position of peaks .…”

Domain-Dependent Surface Adhesion in Twisted Few-Layer Graphene: Platform for Moiré-Assisted Chemistry

“…Further understanding of the domain-dependent adherent origin of nanoparticles could offer a process to manipulate systems of interest in situ, a complementary capability to existing emerging techniques for the study and utilization of twisted heterostructure systems. − ,, Control of such surface manipulation mechanisms could lead to a dynamic approach toward fine control of moiré structures and, more generally, to moiré engineering. Additionally, investigation of domain-dependent adhesion in nongraphene moiré systems could be an avenue for future research. , In particular, moiré superlattices in transition metal dichalcogenide systems offer a rich platform for studying possible domain-dependent surface effects in stacking configurations not yet examined in our work. , …”

“…Additionally, investigation of domain-dependent adhesion in nongraphene moirésystems could be an avenue for future research. 27,28 In particular, moireś uperlattices in transition metal dichalcogenide systems offer a rich platform for studying possible domain-dependent surface effects in stacking configurations not yet examined in our work. 29,30 Overall, our work showcases how moirésystems can serve as a scaffold to generate fine nanostructures in large scale without expensive and scale-limited fabrication techniques.…”