Semimetallic graphene in a modulated electric potential

Abstract

The π-electronic structure of graphene in the presence of a modulated electric potential is investigated by the tight-binding model. The low-energy electronic properties are strongly affected by the period and field strength. Such a field could modify the energy dispersions, destroy state degeneracy, and induce band-edge states. It should be noted that a modulated electric potential could make semiconducting graphene semimetallic, and that the onset period of such a transition relies on the field strength. There exist infinite Fermi-momentum states in sharply contrast with two crossing points (Dirac points) for graphene without external fields. The finite density of states (DOS) at the Fermi level means that there are free carriers, and, at the same time, the low DOS spectrum exhibits many prominent peaks, mainly owing to the band-edge states.

Graphene superlattice with periodically modulated Dirac gap

“…[15][16][17]33,37 Thus, one may conclude that such a reconstruction of the electron spectrum in a certain extent represents a universal property of graphenebased superlattices.…”

Extra Dirac points in the energy spectrum for superlattices on single-layer graphene

“…10, using a tight-binding formalism, the dispersion relation for such a SL can reveal extra Dirac points at the Fermi level 11 . Close to the Fermi level the electronic properties of graphene are well described by the massless 2D Dirac equation.…”

Localization behavior of Dirac particles in disordered graphene superlattices

“…GSL refers to graphene under external periodic scalar [20][21][22][23][24][25][26][27][28] or vector potentials. [28][29][30][31][32][33][34][35][36] Because GSLs further tailor the band dispersion relation of graphene, they may be used to construct graphene-based quantum devices.…”