Propagation of extremely short pulses in a graphene–boron nitride bilayer

In this study we investigate the propagation of extremely short optical pulses in a thin film formed by a graphene grown on a boron nitride substrate. Conduction electrons of the system are described on the basis of the long-wavelength effective Hamiltonian in the case of low temperatures; the electromagnetic field being taken into account within the framework of the classical Maxwell equations. The time evolution of the pulse?s shape for different speeds and maximum amplitudes of an extremely short pulse is analyzed.     

Extremely short optical pulse in a thin-film topological insulator with a hexagonal lattice

The propagation of an extremely short optical pulse in a thin-film topological insulator has been considered. The electrons are described by a low-temperature long-wavelength effective Hamiltonian, whereas the electromagnetic field is treated classically within the Maxwell??s equations. The dependence on the velocity and maximum amplitude of the extremely short pulse has been revealed.     

Propagation of extremely short optical pulses in impurity carbon nanotubes in dispersive and nonlinear media

Maxwell equations describing an extremely short pulse propagating in impurity carbon nanotubes placed in a dispersive nonmagnetic medium are analyzed with allowance for the nonlinearity of the medium. The dependences of the magnetic field intensity on the initial pulse amplitude and the parameters of the medium are revealed.     

High-Harmonic Generation upon Propagation of an Ultimately Short Optical Pulse in a Medium of Carbon Nanotubes Exhibiting Nonlinear Absorption

Optics and Spectroscopy - The problem of propagation of an ultimately short optical pulse in a medium of carbon nanotubes exhibiting nonlinear absorption and gain is analyzed. Nonlinear absorption...     

Ultrashort optical pulse in a defect order-disorder ferroelectric

Physics of the Solid State - The dynamics of an ultrashort optical pulse in order—disorder ferroelectrics in the presence of defects without limitations on the pulse power is considered in...     

Absolute negative conductivity in graphene with the Hubbard interaction in a magnetic field

The current-voltage and current-magnetic field characteristics for a graphene with the electron Hubbard interaction at low temperatures have been calculated in terms of the average electron method. The characteristics obtained have been analyzed as a function of the frequency of the external ac electric field and the magnetic field strength. The portion with an absolute negative conductivity has been revealed.     

Collision of extremely short optical pulses in semiconductor carbon nanotubes

The interaction of extremely short optical pulses in semiconductor carbon nanotubes is discussed. An equation is derived for the dynamics of the electromagnetic field in a system of semiconductor carbon nanotubes at low temperatures, whose solutions are analogs to the solitons of the sine-Gordon equation. The behavior of extremely short optical pulses in semiconductor carbon nanotubes on collision is analyzed.     

Nonlinear Waves in Carbon Nanotubes under Conditions of Electron-Phonon Bonding

Relative simplicity of the atomic structure of carbon nanotubes being hollow cylinders with walls formed by rings of six carbon atoms (generally, the walls can be multilayered) enables the researchers to use this class of substances as model one to reveal the basic mechanisms of the dynamics of quasi-one—dimensional systems. The present work studies the nonlinear properties of carbon nanotubes with strong electron interactions described by the Hubbard Hamiltonian. A microscopic Hamiltonian describing electrons in carbon nanotubes with allowance for the electron mobility, Coulomb repulsion of electrons in one site of carbon nanotubes, and changes in spacing of the neighboring sites caused by acoustic oscillations is suggested. An effective nonlinear system of equations describing the dynamics of electron wave functions within the framework of the suggested Hamiltonian is derived. The existence of nonlinear stable periodic oscillations of electron wave functions in the examined model, in particular, corresponding to acoustic oscillations with different polarization states is established. The influence of the problem parameters on the character of nonlinear wave stability is revealed. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 76–81, June, 2005.