Fermi velocity engineering in graphene by substrate modification

摘要: The Fermi velocity, vF, is one of the key concepts in study a material, as it bears information on variety fundamental properties. Upon increasing demand device applications, graphene viewed prototypical system for engineering vF. Indeed, several efforts have succeeded modifying vF by varying charge carrier concentration, n. Here we present powerful but simple new way to engineer while holding n constant. We find that when environment embedding modified, (i) inversely proportional its dielectric constant, reaching ~ 2.5×106 m/s, highest value any substrate studied so far and (ii) clearly distinguished from an ordinary liquid. method demonstrated here provides route toward velocity two-dimensional electron systems including topological insulators.