Nanobubble superstructure: A tuneable grid of molecule clusters in twisted bilayer graphene
Phys. Rev. B 114, 065414 – Published 13 July, 2026
DOI: https://doi.org/10.1103/f45b-tmbb
Abstract
Highly dense and ordered nanobubble arrays in van der Waals (vdW) heterostructures are crucial for strain engineering electronic devices, fabricating high-capacity energy storage systems, and creating quantum emitters. However, neighboring nanobubbles have been found to spontaneously coalesce because of their interactive strain fields, posing severe limitations in controllability. An interlayer rotation in vdW heterostructures forms superlattices featuring long-wavelength moiré patterns. Here, we show theoretically that these moiré patterns underpin superstructures of perfect arrays of nanobubbles confining molecular clusters in localized regions of the superlattice. We find that nanobubbles spontaneously move towards AA stacking regions, forming ordered arrays with a period that can be tuned by the twist angle. This unprecedented control arises from the modulation of moiré patterns on the local strain field, which turns it into a distinct six-point star shape with rotational symmetry that prevents bubble coalescence. This modulation becomes more prominent with larger dimensions of AA stacking regions—controllable through the bilayer twist angle—and dominates above a critical value. We demonstrate a strategy to engineer the position and density of confined molecule clusters in moiré superlattices. These findings could encourage the experimental exploration of superlattice systems with a tuneable electronic band structure, high energy storage capacity, and precisely positioned quantum emitters.
