Ground state of graphene slabs in an external electric field

Abstract

Unlike graphene ($AB$) stacks, ($ABC$) stacks have two interesting properties: they are topological insulators with only surface states at the Fermi level, and they develop a tunable gap in an external electric field. The total energy of graphene ($AB$) stacks is lower than of ($ABC$) stacks which coincides with the empirical fact that graphite is mainly ($AB$) stacked. An external perpendicular electric field, however, makes ($ABC$) stacks energetically more favorable than ($AB$) stacks. Thus, growing or annealing stacks in an external electric field might become a device to increase the yield in ($ABC$) sequences or even to produce ($ABC$) stacks in a controlled way.