Reshaping of Dirac Cones by Electric Fields

By applying uniform electric fields to topological surface states and metallic graphene armchair nanoribbons, we are able to change the Fermi velocity in a fully dynamical and experimentally feasible way. The topological protection of the Dirac cones is discussed, along with hand-waving arguments that relate to the quantum-confined Stark effect, allowing us understand the physics behind these results.