Multilayer graphene grown at Georgia Tech to heights of 1 to 10 nanometers contains non-graphitic “twists” between layers. Our recent theory describes the top layer as a single, effectively isolated graphene sheet. The remaining multilayer creates a periodically varying mass of the top-layer electrons: from positive, to zero, to negative(!). This makes intuition from single-layer graphene available for the analysis of twisted multilayer graphene, and predicts a regular pattern in the electronic structure that has been observed in experiments from our GT/NIST collaboration.
Real space energy-gap map as observed through
scanning tunneling spectroscopy and explained by