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Showing 1 to 14 of 14 for “"phonon spectra"”.
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Phonon spectra and thermal properties of some fcc metals using embedded-atom potentials /
… we have calculated the dynamical matrices and phonon dispersion curves for six fee metals (Cu,Ag,Au,Ni,Pd and Pt). We have also investigated, within the quasiharmonic approximation, some other thermal properties of these metals which depend on the phonon density of states, such as the …
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The Phonon Spectra of Simple Metals--Higher Order Effects of The Electron-Ion Interaction
Made available in DSpace on 2015-05-12T22:38:44Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 7206925.PDF: 3437634 bytes, checksum: fad225ecf59526ffff0dde7c0acef55a (MD5) Previous issue date: 1971
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The phonon spectra of simple metals - higher order effects of the electron-ion interaction
Calculations of the phonon frequencies in simple metals are carried out takirtg into account the influence of the periodic ionic lattice on the electrons. These effects are calculated by expanding the phonon dynamical matrix in powers of the electron-ion interaction and truncating the series in …
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Raman scattering in free standing porous Si films
… conductivity accompanied by a change in the phonon spectra. Also, comparing Stokes and anti-Stokes Raman spectra, we find that porous Si is a nano-composite material with a complex morphology and variety of crystallites sizes. The porous silicon layers can be used for thermal isolation and as …
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Temperature dependent structural, electronic and optical properties of the Si(100) surface from first principles
… (BOMD), related vibrational states (surface phonons) by calculating the vibrational density of states (VDOS) using a harmonic and anharmonic approach, and the optical response of the Si bulk and Si(100) surface calculating the temperature dependent reflectance anisotropy (RA). The surface …
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Molecular dynamics analysis of spectral characteristics of phonon heat conduction in silicon
… been some lingering questions surrounding the phonon mean free path and importance of different polarizations. This research investigates phonon transport in bulk crystalline silicon using molecular dynamics and lattice dynamics. The interactions are modeled with the environment dependent …
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Ab initio calculations of phonon properties and spectra in condensed matter
Phonons, the quantization of atomic vibrations, are important in studying many solid state properties, ranging from Raman, infrared, and neutron scattering to thermal expansion, specific heat, and heat conductivity to electrical resistivity and superconductivity. Generally, modeling the interatomic …
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Computational Modeling of Geometry Dependent Phonon Transport in Silicon Nanostructures
… depend on nanostructure boundary geometry. Phonons are quantized mechanical vibrations that are the dominant carrier of heat in semiconductor materials and their aggregate behavior determine a nanostructure's thermal performance. Phonon-geometry scattering processes as well as waveguiding …
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Light scattering studies of phonon anomalies and superconductivity in A15 compounds
Light scattering studies of phonon anomalies and superconductivity in A15 compounds and Nb, V, and Ta are presented. The experimental methods included one-and two-phonon and electronic Raman scattering and Brillouin scattering from Surface Acoustic Waves (SAWs). The Eg optic phonon in V3Si, Nb~n, …
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Light scattering studies of heavy fermion and high Tc superconductors
… are used to probe the diverse excitation spectra of heavy fermion and high T c superconductors. Our studies of heavy fermion compounds principally demonstrate the efficacy of using light scattering techniques to probe spin fluctuations and crystal field excitations in metals. For example, …
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Towards Machine Learning Foundation Models for Materials Chemistry
… theory (DFT) in 36 diverse test cases, including phonon spectra, ammonia/borane, amorphous carbon, aqueous interfaces, batteries, carburane, cathode materials, combustion, dichalcogenides, dislocation, dissolution, heterogeneous catalysis, hydrogen, ice & water, MOFs, molten salts, multi-component …
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Ultrahigh resolution surface phononics
Phonons are one of the most important quasiparticles in condensed matter physics; they influence a wide range of physical properties ranging from thermal and electrical conductivity to the propagation of sound. Phonons are also crucial to emerging research fields such as quantum information and …
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Resonance Raman spectroscopy of single-walled carbon nanotubes
The unusual one-dimensional properties of phonons in crystalline arrays of carbon nanotubes is presented. The main technique for probing the phonon spectra is Raman spectroscopy and the many unique and unusual features of the Raman spectra of carbon nanotubes are highlighted. Various features of …
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Computational Study of Two-Dimensional Materials for Energy Applications
… parameter reveals negative values for the ZA phonon branch. A negative thermal expansion of the hBN sheet in the range ∼0-600 K is observed which increased with increasing layer number. <br/><br/>Experimental measurements on the thermal expansion confirmed a negative expansion in the 293-423 K …