University of Texas at Dallas scientists are investigating how structures made from several layers of graphene stack up in terms of their fundamental physics and their potential as reconfigurable semiconductors for advanced electronics. Since graphene’s first isolation in 2004 — which later led to a Nobel Prize in physics — scientists and engineers have intensely studied its unique physical properties as well as its potential applications. In contrast, rhombohedral stacking, or ABC stacking, features a unidirectional, or chiral, 60-degree rotation for each successive layer. “Hexagonal stacking is more structurally stable, but rhombohedral stacking is much more remarkable because the chirality in stacking can make the electrons strongly correlated for extraordinary macroscopic quantum phenomena,” Zhang said. A graphene few-layer sample typically consists of a combination of hexagonal graphene and rhombohedral graphene.