Tailoring the Energy Landscape of Graphene Nanostructures on Graphene and Manipulating Them Using Tilt Grain Boundaries

Abstract

In two-dimensional van der Waals (vdW) materials, the relative twist angle between adjacent layers not only controls their electronic properties but also determines their stacking energy. This effect makes it difficult to stabilize the vdW materials with twist angles. Here, we demonstrate that we can controllably stabilize the system with custom-designed twist angles, for example, magic angle, which is realized by tailoring the adhesive-energy landscape of graphene nanostructures on graphene by using a one-dimensional tilt grain boundary (GB). Our result demonstrates that the flat band of the custom-built nanoscale magic-angle-twisted bilayer graphene is still robust, even when its size is comparable to a single moir\'e spot. Moreover, in our experiments, the area ratio with different stacking orders separated by the tilt GB can be continuously tuned by using the scanning-tunneling-microscope tip, and we can repeatedly fold and unfold the graphene nanostructure along the one-dimensional GB, demonstrating the ability to manipulate the graphene nanostructure at the atomic scale.