Related papers: Optical vibrations in alkali halide crystals
Using the Boltzmann equation for electrons in metals, we show that the optical phonons soften and have a dispersion due to screening in agreement with the results reported recently [M. Reizer, Phys. Rev. B {\bf 61}, 40 (2000)]. Additional…
We explicitly derive the wavefunctions of chiral phonons propagating along the helical axis in chiral crystals and clarify the characteristics of electron-phonon interactions in chiral helical crystals. In particular, we elucidate how the…
We present new relations for calculation of phonon polaritons, plasmons and plasmon polaritons frequencies, which differ from the standard relations. So, we study the frequency of phonon polaritons in a two dimensional lattice with…
Two-dimensional hybrid organic-inorganic metal halide perovskites offer enhanced stability for perovskite-based applications. Their crystal structure's soft and ionic nature gives rise to strong interactions between charge carriers and…
The strong coupling between elementary excitations of the electromagnetic field (photons) and quantized mechanical vibrations (phonons) produces hybrid quasi-particle states, known as phonon-polaritons. Their typical signature is the…
We present a theoretical description of the coupling between longitudinal optical phonons and collective excitations of a two-dimensional electron gas. By diagonalizing the Hamiltonian of the system, including Coulomb electron-electron and…
We report a device that provides coherent emission of phonon polaritons, a mixed state between photons and optical phonons in an ionic crystal. An electrically pumped GaInAs/AlInAs quantum cascade structure provides intersubband gain into…
In this work we investigate anharmonic vibrational polaritons formed due to strong light-matter interactions in an optical cavity between radiation modes and anharmonic vibrations beyond the long-wavelength limit. We introduce a…
Recently there has been paid much attention to phenomena caused by local anharmonic vibrations of the guest ions encapsulated in polyhedral cages of materials such as pyrochlore oxides, filled skutterdites and clathrates. We theoretically…
Phonons diffraction and interference patterns are observed at the atomic scale, using molecular dynamics simulations in systems containing crystalline silicon and nanometric obstacles as voids or amorphous-inclusions. The diffraction…
We present results of first-principles calculations of the frequency-dependent polarizabilities of all alkali atoms for light in the wavelength range 300-1600 nm, with particular attention to wavelengths of common infrared lasers. We…
We report a laser that coherently emits phonon-polaritons, quasi-particles arising from the coupling between photons and transverse optical phonons. The gain is provided by an intersubband transition in a quantum cascade structure. The…
We investigate the long-wavelength dispersion of longitudinal and transverse optical phonon modes in polar two-dimensional materials, multilayers, and their heterostructures. Using analytical models and density-functional perturbation…
Digital video-microscopy measurements are reported of both elastic bandstructures and overdamped phonon decay times in two-dimensional colloidal crystals. Both quantities together allow to determine the friction coefficients along various…
Localized modes of large amplitudes in nonlinear lattices are considered. The applied method allows the reduction of nonlinear problem to a linear inverse problem of phonons scattering on a local potential. The method is efficient in the…
The polaron features for long-range electron-phonon interaction are investigated by extending a variational approach previously proposed for the study of systems with local coupling. The ground-state spectral weight, the average kinetic…
We predict high-order harmonics in which the polarization within the spectral bandwidth of each harmonic varies continuously and significantly. For example, the interaction of counter-rotating circularly-polarized bichromatic drivers having…
The electric dipole polarizabilities evaluated at imaginary frequencies for hydrogen, the alkali-metal atoms, the alkaline earth atoms, and the inert gases are tabulated along with the resulting values of the atomic static polarizabilities,…
Photonic crystals are periodic structures which prevent light propagation along one or more directions in certain frequency intervals. Their band spectrum is usually analyzed using Floquet-Bloch decomposition. This spectrum is located on…
With polarized and angle-resolved Raman spectroscopy studies on single two-dimensional layered perovskites (2DLP) flakes with different ammonium molecules as organic cations, in 2020 we revealed the very rich phonon spectra in the…