arXiv subjects

O. V. Kibis

Publications and source records attributed to O. V. Kibis.

64 records · Page 4Linked to original sources

arXiv2012

Persistent current induced by quantum light

It is demonstrated that the strong coupling of an electron gas to photons in systems with broken time-reversal symmetry results in bound electron-photon states which cannot be backscattered elastically. As a consequence, the electron gas can flow without dissipation. This quantum macroscopic phenomenon leads to the unconventional superconductivity which is analyzed theoretically for a two-dimensional electron system in a semiconductor quantum well exposed to an in-plane magnetic field.

cond-mat.mes-hall↗

arXiv2012

Asymmetric quantum dot in microcavity as a nonlinear optical element

We have investigated theoretically the interaction between individual quantum dot with broken inversion symmetry and electromagnetic field of a single-mode quantum microcavity. It is shown that in the strong coupling regime the system demonstrates nonlinear optical properties and can serve as emitter of the terahertz radiation at Rabi frequency of the system. Analytical results for simplest physical situations are obtained and numerical quantum approach for calculating emission spectrum is developed.

cond-mat.mes-hall↗

arXiv2011

Band gap in graphene induced by vacuum fluctuations

The electrons in undoped graphene behave as massless Dirac fermions. Therefore graphene can serve as an unique condensed-matter laboratory for the study of various relativistic effects, including quantum electrodynamics (QED) phenomena. Although theoretical models describing electronic properties of graphene have been elaborated in details, the QED effects were usually neglected. In this paper we demonstrate theoretically that QED can drastically modify electronic properties of graphene. We predict the following QED effect - the opening of the band gap in a graphene monolayer placed inside a planar microcavity filled with an optically active media. We show that this phenomenon occurs due to the vacuum fluctuations of the electromagnetic field and is similar to such a well-known phenomenon as a vacuum-induced splitting of atomic levels (the Lamb shift). We estimate the characteristic value of the band gap and find that it can sufficiently exceed the value of the Lamb shift.

cond-mat.mes-hall↗

arXiv2011

Dissipationless electron transport in photon-dressed nanostructures

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.

cond-mat.mes-hall↗

arXiv2010

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.

cond-mat.mes-hall↗

arXiv2009

Magnetic Moment Coupling to Circularly Polarized Photons

Exact stationary solutions of the wave equation are obtained to describe the interaction between magnetic moment of elementary particle and circularly polarized photons. The obtained solutions substantially modify the conventional model of field-matter interaction. It follows from them that magnetic moment couples to photons, and this coupling leads to bound particle-photon states with different energies for different orientations of magnetic moment. As a consequence, the interaction splits particle states differing by directions of total angular momentum. Stationary spin splitting, induced by photons, and concomitant effects can be observed for particles exposed to a laser-generated circularly polarized electromagnetic wave.

quant-ph↗

arXiv2009

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

We demonstrate theoretically the parametric oscillator behavior of a two-level quantum system with broken inversion symmetry exposed to a strong electromagnetic field. A multitude of resonance frequencies and additional harmonics in the scattered light spectrum as well as altered Rabi frequency are predicted to be inherent to such systems. In particular, dipole radiation at the Rabi frequency appears to be possible. Since the Rabi frequency is controlled by the strength of coupling electromagnetic field, the effect can serve for the frequency-tuned parametric amplification and generation of electromagnetic waves. Manifestation of the effect is discussed for III-nitride quantum dots with strong build-in electric field breaking the inversion symmetry. Terahertz emission from arrays of such quantum dots is shown to be experimentally observable.

quant-ph↗

arXiv2008

Superlattice properties of semiconductor nanohelices in a transverse electric field

A charge carrier confined in a quasi-one-dimensional semiconductor helical nanostructure in the presence of an electric field normal to the axis of the helix is subjected to a periodic potential proportional to the strength of the field and the helix radius. As a result, electronic properties of such nanohelices are similar to those of semiconductor superlattices with parameters controlled by the applied field. These properties include Bragg scattering of charge carriers by a periodic potential, which results in energy gap opening at the edge of the superlattice Brillouin zone. This provides an opportunity for creating a new class of tunable high-frequency devices based on semiconductor nanohelices.

cond-mat.other↗

arXiv2006

Terahertz emitters and detectors based on carbon nanotubes

We formulate and justify several proposals utilizing the unique electronic properties of different types of carbon nanotubes for a broad range of applications to THz optoelectronics, including THz generation by hot electrons in quasi-metallic 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.

cond-mat.mtrl-sci↗

arXiv2005

Superlattice properties of carbon nanotubes in a transverse electric field

Electron motion in a (n,1) 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 (n,1) 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 bandstructure is shown to be significant for experimentally attainable electric fields, which raises the possibility of applying this effect to novel nanoelectronic devices.

cond-mat.other↗