O. V. Kibis

Metal-insulator transition in graphene induced by circularly polarized photons

Exact stationary solutions of the electron-photon Dirac equation are obtained to describe the strong interaction between massless Dirac fermions in graphene and circularly polarized photons. It follows from them that this interaction forms bound electron-photon states which should be considered as a kind of charged quasiparticles. The energy spectrum of the quasiparticles is of dielectric type and characterized by an energy gap between the valence and conductivity bands. Therefore the electron-photon interaction results in metal-insulator transition in graphene. The stationary energy gap, induced by photons, and concomitant effects can be observed for graphene exposed to a laser-generated circularly polarized electromagnetic wave.

Carbon nanotubes as a basis for terahertz emitters and detectors

We propose and justify two schemes utilizing the unique electronic properties of carbon nanotubes for novel THz applications including tunable THz generation by hot electrons in quasi-metallic nanotubes and THz radiation detection by armchair nanotubes in strong magnetic fields.

Superlattice properties of carbon nanotubes in a transverse electric field

Electron motion in a

Carbon nanotubes: A new type of emitter in the terahertz range

(n,1)

Terahertz processes in carbon nanotubes

carbon nanotube is shown to correspond to a de Broglie wave propagating along a helical line on the nanotube wall. This helical motion leads to periodicity of the electron potential energy in the presence of an electric field normal to the nanotube axis. The period of this potential is proportional to the nanotube radius and is greater than the interatomic distance in the nanotube. As a result, the behavior of an electron in a

Dissipationless electron transport in photon-dressed nanostructures.

(n,1)

Matter Coupling to Strong Electromagnetic Fields in Two-Level Quantum Systems with Broken Inversion Symmetry

nanotube subject to a transverse electric field is similar to that in a semiconductor superlattice. In particular, Bragg scattering of electrons from the long-range periodic potential results in the opening of gaps in the energy spectrum of the nanotube. Modification of the band structure is shown to be significant for experimentally attainable electric fields, which raises the possibility of applying this effect to nanoelectronic devices.

Control of electronic transport in graphene by electromagnetic dressing.

It is theoretically demonstrated that the electric-field-induced heating of the electron gas in carbon nanotubes can lead to population inversion in the electron subbands, which results in the generation of electromagnetic waves in the terahertz range by hot electrons. This phenomenon can be used for the creation of radiators of a new type, based on carbon nanotubes, for the terahertz frequency range.

Superlattice Properties of Helical Nanostructures in a Transverse Electric Field

We investigated several proposals utilizing the unique electronic properties of carbon nanotubes (CNTs) for a broad range of applications to THz optoelectronics, including THz generation by Cerenkov-type emitters based on carbon nanotubes and by hot electrons in quasimetallic nanotubes, frequency multiplication in chiral-nanotube-based superlattices controlled by a transverse electric field, and THz radiation detection and emission by armchair nanotubes in a strong magnetic field. Dispersion equations of the electron beam instability and the threshold conditions of the stimulated emission have been derived and analyzed, demonstrating realizability of the nanotube-based nanoFEL at realistic parameters of nanotubes and electronic beams.

Transport properties of a two-dimensional electron gas dressed by light

It is shown that the electron coupling to photons in field-dressed nanostructures can result in the ground electron-photon state with a nonzero electric current. Since the current is associated with the ground state, it flows without the Joule heating of the nanostructure and is nondissipative. Such a dissipationless electron transport can be realized in strongly coupled electron-photon systems with the broken time-reversal symmetry--particularly, in quantum rings and chiral nanostructures dressed by circularly polarized photons.