Kinetics of Nanobubbles in Tiny-Angle Twisted Bilayer Graphene

Realization of high-quality van der Waals (vdWs) heterostructures by stacking two-dimensional (2D) layers requires atomically clean interfaces. Because of strong adhesion between the constituent layers, the vdWs forces could drive trapped contaminants together into submicron-size '' bubbles '', which leaves large interfacial areas atomically clean. Here, we study the kinetics of nanobubbles in tiny-angle twisted bilayer graphene (TBG) and our results reveal a substantial influence of the moire ' superlattice on the motion of nanoscale interfacial substances. Our experiments indicate that the bubbles will mainly move along the triangular network of domain boundaries in the tiny-angle TBG when the sizes of the bubbles are comparable to that of an AA-stacking region. When the size of the bubble is smaller than that of an AAstacking region, the bubble becomes motionless and is fixed in the AA-stacking region, because of its large out-of-plane corrugation. KEYWORDS: twisted bilayer graphene, domain wall, bubbles, self-cleaning, scanning tunneling microscopy

Automated summary

This study investigates the dynamics of nanobubbles in tiny-angle twisted bilayer graphene (TBG) and reveals the significant influence of the moire superlattice on the motion of nanoscale interfacial substances.