نتایج جستجو برای: phonon spectrum
تعداد نتایج: 237709 فیلتر نتایج به سال:
In this paper, we study the phonon thermal properties of a ladder nanostructure in harmonic approximation. We present a model consisting of two infinite chains with different masses. Then, we investigate the effect of different masses on the phonon spectrum. Moreover, as a specific case, in the absence of the second neighbor interaction, we calculate the phonon density of states/modes. Finally...
Single crystals of Ba1-xKxBiO3 compound for 0 < x <0.6 from insulator to superconducting region have been grown by electrochemical method. The crystals have been characterized by powder x-ray diffraction and Laue x-ray to determine the crystal structure, formed phases and potassium concentration. Inelastic x-ray scattering spectrum of the crystals has been studied to investigate the phonon pro...
In this paper, we study the phonon and thermal properties of a nanocrystal by using transfer matrix method in the harmonic approximation. The considered system is a mass-spring nanocrystal with a square cross section. At first, for the ideal case, we obtain the phonon spectrum with free boundary conditions. Then we calculate some phonon transport properties of this system, namely, the phonon de...
In this paper, we investigate the phonon transmission coefficient of a mass-spring in the presence of Kohn interaction by using Green’s function method within the harmonic approximation. This system is embedded between two simple phononic leads including only the nearest neighbor interactions. The results show that the presence of Kohn and the nearest neighbor interactions in the center wire m...
In this paper, according to the density functional theory and semiharmonic approximation and solving kohen's equations using plane wave, band structure, phonon scattering; Dielectric tensor, Bourne effective charge, Raman cross-section; We calculated the infrared and specific heat capacity of indium phosphide in two-phase structures on zincblend (ZB) and salt rock (Rs). The results show that t...
In this paper, the phonon, dynamic and thermal properties of indium nitride in two phases are investigated. The calculations are performed using the pseudopotantial method in the framework of density functional theory and by using the quantum-espresso Package. In the calculations, the exchange-correlation terms of LDA, GGA and PBE0 approximation are used. Investigation of phononic properties s...
Static properties, relatively intensity noise and intensity modulation response in quantum cascade lasers (QCLs) studied theoretically in this paper. The present rate equations model consists of three equations for the electrons density in the conduction band and one equation for photons density in cavity length. Two equations were derived to calculate the noise and modulation response. Calcula...
The spectrum of electron-phonon complexes in monolayer graphene is investigated in the presence of a perpendicular quantizing magnetic field. Despite the small electron-phonon coupling, usual perturbation theory is inapplicable for the calculation of the scattering amplitude near the threshold of optical phonon emission. Our findings, beyond perturbation theory, show that the true spectrum near...
The phonon spectrum of Coulomb lattice in neutron star crusts above the neutron drip density is affected by the interaction with the ambient neutron Fermi-liquid. For the values of the neutron-phonon coupling constant in the range 0.1 ≤ λ ≤ 1 an appreciable renormalization of the phonon spectrum occurs which can lead to a lattice instability manifested in an exponential growth of the density fl...
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