Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 696 for “"phonon"”.
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Phonon imaging
This thesis describes the development of the phonon imaging method. This technique permits the direct measurement of the angular and temporal distribution of phonons emitted from a point source of heat in insulators at low temperatures. It is a derivative of the ballistic heat pulse method, but one …
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Phonon-mediated Casimir effect
… this thesis, we develop the description of the phonon-mediated Casimir interaction taking into account multiple phonon-impurity scatterings, that strongly renormalize the resulting interaction between the impurities. Our results, formulated in terms of the T-matrix formalism, generalize previous …
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Study of phonon transmission through solid-solid interfaces and superlattices by phonon imaging
… the low-temperature propagation of heat pulses (phonons) through crystals and across solid-solid interfaces. The phonon imaging technique has been used to examine the angular and temporal dependence of the phonon-flux intensity in several systems, listed below. 1. Phonon focusing in cubic …
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Phonon Dispersion Relations in Chrystals
… from a single crystal enables us to deduce the phonon dispersion relation, that is the frequency of the normal modes as a function of their wave vectors. These experiments provide a far more direct test of theories of crystal dynamics than do specific heat measurements. The possibility of …
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Phonon thermal transport at the nanoscale
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2015-07-22 without embargo terms
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Ultrafast Ultra-confined Plasmon Phonon Interactions
… nanometrically confined ultrafast plasmon-phonon interactions. Nanometric plasmonic confinement is achieved by coupling the charge oscillations of a single gold nanoparticle to a gold substrate. This confines the plasmonic field to the single nanometre gap separating the two and is known as …
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Phonon polariton interaction with patterned materials
The generation, propagation and detection of THz phonon polaritons are studied through both femtosecond pump-probe techniques, and Finite Difference Time Domain (FDTD) simulations in this thesis. The theory surrounding the driving, propagation and detection of these modes is treated in a consistent …
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Brillouin scattering and coherent phonon generation.
Massachusetts Institute of Technology. Dept. of Physics. Thesis. 1965. Ph.D.
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Phonon hydrodynamic transport at elevated temperature
For over half a century, phonon hydrodynamic transport was deemed exotic and mattered only at extremely low temperatures. In this work, by combining the theoretical and experimental approach, we successfully predict and confirm the existence of phonon hydrodynamic transport in graphite above 200 K. …
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Computational Methods for Studying Phonon Dynamics
… of the structure’s normal modes, often termed phonons, which are collective motions of atoms vibrating at certain frequencies. These vibrational modes play important roles in a variety of material properties and physical phenomena such as chemical reactions, phase transitions, mass/ion …
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Machine Learning for Phonon Thermal Transport
… change. As one of the major energy carriers, phonons play an indispensable role in various energy-related processes. The past decades witnessed continuous development in phonon measurements and computation techniques. However, at least two significant challenges impede our further exploration …
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Experiments to investigate phonon-nuclear interactions
… designed to test for and investigate a proposed phonon-nuclear coupling interaction and an associated nuclear excitation transfer mechanism. Electric and magnetic interactions of phonons with atomic nuclei have been studied for several decades. However, such second-order interactions are too weak …
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Phonon hydrodynamic transport at elevated temperature
For over half a century, phonon hydrodynamic transport was deemed exotic and mattered only at extremely low temperatures. In this work, by combining the theoretical and experimental approach, we successfully predict and confirm the existence of phonon hydrodynamic transport in graphite above 200 K. …
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Phonon Spectroscopy and Low-Dimensional Electron Systems
… propagation of pulses of nonequilibrium acoustic phonons and their interaction with semiconductor nanostructures are investigated. Such studies can give unique information about the properties of low-dimensional electron systems, but in order to interpret the experiments and to understand the …
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Phonon Thermal Transport in Non-Crystalline Materials
Submitted by Jesse Garrison (jagarris@illinois.edu) on 2012-01-09T22:09:40Z No. of bitstreams: 1 1975_zaitlin.pdf: 4748430 bytes, checksum: 1b58a9b1eed5b1569f286984be435f46 (MD5)
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A search for a new phonon detector
… in the development of a tunable monochromatic phonon detector for use in experiments investigating the transmission of phonons (v > 10 GHz) through 4He at T S 0.1 K and 0 < P < 24 bars is described. The technique studied was the use of a magnetically tuned spin 1/2 system whose change in …
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Dispersive phonon imaging in III-V semiconductors
… transport properties of high-frequency acoustic phonons are investigated in GaAs, InSb, InP and InAs using the phonon-imaging technique. In this method, a focused laser beam provides a movable heat source on one side of a cooled crystal (~ 2 K). A single small phonon detector on the opposite face …
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Magnon and phonon thermal transport in oxides
… the understanding of the mechanism of magnon and phonon thermal transport in oxides. In these studies, I use ultrafast pump-probe metrology, time-domain thermoreflectance to measure the thermal conductivity. The first subject is the relationship between magnons and phonons in low-dimensional …
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The electron-phonon interaction in normal metals
Massachusetts Institute of Technology. Dept. of Physics. Thesis. 1967. Ph.D.
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Phonon-polaritons in bulk and patterned materials
… thesis explores the spectroscopic properties of phonon-polaritons, which are admixtures of coupled electromagnetic and mechanical vibrations in polar crystals. An in-depth theoretical treatment supplemented with simulations of experimental results of a four-wave mixing impulsive stimulated Raman …
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