Abstract
We demonstrated theoretically that the renormalization of the electron energy spectrum near the Dirac point of graphene by a strong high-frequency electromagnetic field (dressing field) drastically depends on polarization of the field. Namely, linear polarization results in an anisotropic gapless energy spectrum, whereas circular polarization leads to an isotropic gapped one. As a consequence, the stationary (dc) electronic transport in graphene strongly depends on parameters of the dressing field: A circularly polarized field monotonically decreases the isotropic conductivity of graphene, whereas a linearly polarized one results in both giant anisotropy of conductivity (which can reach thousands of percents) and the oscillating behavior of the conductivity as a function of the field intensity. Since the predicted phenomena can be observed in a graphene layer irradiated by a monochromatic electromagnetic wave, the elaborated theory opens a substantially new way to control electronic properties of graphene with light.
Highlights
Since the discovery of graphene1, it has attracted the persistent interest of the scientific community
We will restrict our consideration to the case of electron states near the Dirac point of a single graphene sheet subjected to an electromagnetic wave propagating perpendicularly to the graphene plane
We have shown that the transport properties of electrons in graphene are strongly affected by a dressing field
Summary
Let us focus our attention on the dc conductivity of the dressed electrons. Generally, the density of the conduction electrons can be tuned by applying a bias voltage which fixes the Fermi energy, εF, of electron gas. Assuming the Fermi energy to be in the conduction band and the temperature to be zero, let us apply a stationary (dc) electric field E = (Ex, E y) to the graphene sheet It follows from the conventional Boltzmann equation for conduction electrons (see, e.g., Refs 2,52) that the electric current density, J, is given by the expression. The energy spectrum of electrons dressed by a circularly polarized field [2] is isotropic and has the field-induced gap [3] at the Dirac point. The energy spectrum of electrons dressed by the linearly polarized field [5] is gapless and has the field-induced anisotropy arisen from the Bessel function in Eq [7]. They do not influence on low-energy electronic transport under consideration
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