Bipolar electron waveguides in graphene

Abstract

We show analytically that the ability of Dirac materials to localize an electron in both a barrier and a well can be utilized to open a pseudogap in graphene's spectrum. By using narrow top gates as guiding potentials, we demonstrate that graphene bipolar waveguides can create a nonmonotonous one-dimensional dispersion along the electron waveguide, whose electrostatically controllable pseudoband gap is associated with strong terahertz transitions in a narrow frequency range.