Researchers have found that three-layer graphene can automatically arrange itself into specific stacking formations (ABA/ABC domains) during its growth on silicon carbide. This innovation could facilitate larger-scale production of quantum devices.
Graphene, consisting of a single layer of carbon atoms in a two-dimensional honeycomb structure, possesses remarkable characteristics: it is roughly 200 times stronger than steel, lightweight, flexible, and an excellent conductor of electricity and heat. These unique properties make graphene increasingly valuable in various domains, such as electronics, energy storage, medical technologies, and, more recently, quantum computing.
The quantum characteristics of graphene, like superconductivity and other distinct quantum phenomena, appear when its atomic layers are precisely stacked and twisted to form “ABC stacking domains.” Traditionally, creating ABC stacking domains necessitated the exfoliation of graphene and the painstaking process of twisting and aligning the layers to specific orientations — a complex method that is hard to scale for large-scale industrial use.
Researchers from NYU Tandon School of Engineering, guided by Elisa Riedo, a Herman F. Mark Professor in Chemical and Biomolecular Engineering, have made a groundbreaking discovery in graphene research. They observed self-organizing ABA and ABC stacking domains driven by growth, a finding that could catalyze advancements in quantum technology. This research, published recently in the Proceedings of the National Academy Of Sciences (PNAS), illustrates how certain stacking configurations in three-layer epitaxial graphene systems can emerge spontaneously, bypassing the need for the intricate and non-scalable methods typically employed in graphene twisting production.
The team, which included Martin Rejhon, a former post-doctoral fellow at NYU, has detected the self-assembly of ABA and ABC domains in a three-layer epitaxial graphene setup grown on silicon carbide (SiC). Utilizing advanced conductive atomic force microscopy (AFM), they discovered that these domains form autonomously without requiring manual intervention. This unprompted organization is a significant advancement in the manufacturing of graphene stacking domains.
The formation and dimensions of these stacking domains are shaped by the combination of strain and the structures of the three-layer graphene areas. Some domains develop as narrow stripe-like shapes, just tens of nanometers wide and extending over microns, presenting exciting possibilities for future applications.
Riedo noted, “In the future, we could manage the size and placement of these stacking structures through pre-growth patterning of the SiC substrate.”
The emergence of these self-assembled ABA/ABC stacking domains may lead to groundbreaking developments in quantum devices. Their stripe-like configurations are particularly advantageous for facilitating unconventional quantum Hall effects, superconductivity, and charge density waves. Such advancements could open up new pathways for scalable electronic devices that take advantage of graphene’s quantum features.
This finding represents a significant advancement in graphene studies, bringing researchers closer to harnessing the full potential of this extraordinary material for the next generation of electronic and quantum technologies.
This research was funded by the U.S. Army Research Office under Award # W911NF2020116 and also involved scientists from Charles University, Prague.
