نتایج جستجو برای: longitude optical phonon

تعداد نتایج: 282714  

A simple semi-phenomenological model, which accurately predicts the dependence of thresholdcurrent for temperature of Resonant-phonon three well quantum cascade laser based on verticaltransitions is offered. We found that, the longitude optical phonon scattering of thermally excitedelectrons is the most important limiting factor for thermal performance of high frequency THz QCLs.In low frequenc...

Journal: :journal of artificial intelligence in electrical engineering 2013
aida gholami hassan rasooly

a simple semi-phenomenological model, which accurately predicts the dependence of thresholdcurrent for temperature of resonant-phonon three well quantum cascade laser based on verticaltransitions is offered. we found that, the longitude optical phonon scattering of thermally excitedelectrons is the most important limiting factor for thermal performance of high frequency thz qcls.in low frequenc...

Journal: :journal of sciences islamic republic of iran 0

a theory is presented for the dispersion relations of the nonlinear phonon-polaritons arising when phonons are coupled to the electromagnetic waves in multilayered structures of nonlinear materials. the calculations are applied to a multilayered structure consisting of a thin film surrounded by semi-infinite bounding media where each layer may have a frequency dependent dielectric function and ...

A theory is presented for the dispersion relations of the nonlinear phonon-polaritons arising when phonons are coupled to the electromagnetic waves in multilayered structures of nonlinear materials. The calculations are applied to a multilayered structure consisting of a thin film surrounded by semi-infinite bounding media where each layer may have a frequency dependent dielectric function and ...

In this paper, the phononic and thermal properties of tungsten disulfide have been studied. The aim of this study was to investigate the phonon and thermal properties such as heat capacity and enthalpy. The calculations are performed within the framework of density functional theory by pseudo-potential methood and by Quantum Espresso computational package and their exchange-correlation function...

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...

2011
Hrvoje Buljan Marinko Jablan Marin Soljačić

We predict the existence of coupled plasmon-phonon excitations in graphene by using the self-consistent linear response formalism. The unique electron-phonon interaction in graphene leads to unconventional mixing of plasmon and optical phonon polarizations. We find that longitudinal plasmons couple exclusively to transverse optical phonons, whereas graphene’s transverse plasmons couple only to ...

2010
Jedo Kim Massoud Kaviany

Using the observed temperature dependence of a-Si:H photon absorption spectrum and the weak-phonon interaction second-order transition theory, phonon-coupling enhanced photon absorption is predicted for a-Si-Ge and a-Si-Sn alloys. The ab initio calculated electron and phonon properties of the alloyed amorphous phase show minimally altered electronic states and significant redshifted phonon ener...

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...

Journal: :Nano letters 2007
Concetta Nobile Vladimir A Fonoberov Stefan Kudera Antonio Della Torre Antonio Ruffino Gerwin Chilla Tobias Kipp Detlef Heitmann Liberato Manna Roberto Cingolani Alexander A Balandin Roman Krahne

We investigated the optical phonon excitations of laterally aligned nanorod arrays by resonant Raman scattering. We observed a strong suppression of the surface-optical phonon modes in the closely packed aligned arrays and a small asymmetry in the longitudinal-optical phonon peak with respect to the rod alignment orientation. These observations can be explained by the spatial distribution of th...

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