Stacking two sheets of graphene—and slightly twisting one relative to the other—creates a material that exhibits a rich array of electronic phenomena. Ranging from exotic insulating behavior to unconventional superconductivity, such effects arise from an interplay between strong electron–electron interactions and topologically nontrivial electronic bands. The flat, low-energy bands of twisted bilayer graphene are central to many of these phenomena, but the coupling of those bands to higher-energy ones has been poorly understood. Now Pierre Pantaleón of IMDEA Nanoscience in Spain and his colleagues have studied how changing the twist angle affects this coupling and, in turn, the material’s electron density and topological properties [1]. The results could help scientists use twisted bilayer graphene for applications in quantum computing and other quantum information technologies.
To read more, click here.