The polar optical vibrations are essential for the transport properties in semiconductor nanostructures because they are the source of a strong electron-phonon interaction. The commonly used macroscopic models (see for [1] and the bibliography therein) treat the optical phonon displacements as a spatially smooth functions. Our calculation in the realistic three-dimensional lattice-dynamical mod...

for the lattice constants i.e. 11 C , 12 C , 44 C , 44 12 C C − , 44 12 C C and bulk modulus B obtained using the Hartree (H) local field correction function has higher values in comparison with the results obtained for the same properties using Ichimaru-Utsumi (IU) local field correction function. The results for the Shear modulus ( C ′ ), deviation from Cauchy’s relation, Poisson’s ratio σ , ...

The lattice dynamics of the silica polymorph α-cristobalite has been investigated by a combination of diffuse and inelastic x-ray scattering and ab initio lattice dynamics calculations. Phonon dispersion relations and vibrational density of states are reported and the phonon eigenvectors analysed by an intensive comparison of scattering intensities. The experimentally validated calculation is u...

We study the thermal properties of ultra-narrow silicon nanowires (NW) with diameters from 3 nm to 12 nm. We use the modified valence-force-field method for computation of phononic dispersion and the Boltzmann transport equation for calculation of phonon transport. Phonon dispersion in ultra-narrow 1D structures differs from dispersion in the bulk and dispersion in thicker NWs, which leads to d...

It has been found experimentally as well as theoretically that the lattice thermal conductivity can be largely reduced by the size confinement effect. The significant boundary scattering effect is one of the dominant factors. In most existing lattice thermal conductivity models, an empirical relation is used for this scattering rate. An unconfined or confined phonon distribution obtained based ...

We have simulated the heat conduction characteristics of finite length single walled carbon nanotubes (SWNTs) with the molecular dynamics method [1-3] with Tersoff-Brenner bond order potential. Temperature at each end of a SWNT was controlled by the phantom technique, and the thermal conductivity was calculated with Fourier’s law from the measured temperature gradient and the energy budgets in ...

To elucidate the three-way relationship among a crystal’s structure, its phonon dispersion characteristics, and its thermal conductivity, an analysis is conducted on layered diatomic Lennard-Jones crystals with various mass ratios. Lattice dynamics theory and molecular dynamics simulations are used to predict the phonon dispersion curves and the thermal conductivity. The layered structure gener...

The quasi two-dimensional electron gas on a metal film can transmit to the surface even minute mechanical disturbances occurring in the depth, thus allowing the gentlest of all surface probes, helium atoms, to perceive the vibrations of the deepest atoms via the induced surface-charge density oscillations. A density functional perturbation theory (DFPT) and a helium atom scattering study of the...