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Showing 1 to 20 of 98 for “"Phonon coupling"”.
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Effects of vacancies and electron temperature on the electron phonon coupling in cubic silicon carbide and their connection to the inelastic thermal spike
<p>“The electron-phonon interaction is an important interaction in many solids as it influences transport phenomena and related quantities such as the electrical and thermal conductivities, especially in nuclear and space applications. The importance of the electron-phonon interaction in primary …
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Upper critical magnetic field of superconducting films with magnetic impurities
… and MakL This theory assumes that the electron-phonon coupling is weak, and that the interaction between the impurity spins and the conduction electron spins is weak. The theory predicts that the pair-breaking effect of the magnetic impurities is temperature-independent, and that the …
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Effects of Ultrathin Interlayers on Thermal Boundary Conductance at Metal-Dielectric Interfaces
… a plateau. Our results reveal that the electron-phonon coupling strength of an interlayer plays a significant role in determining the overall thermal boundary conductance. Analysing heat transport mechanisms across a variety of metal-dielectric interfaces by means of an interlayer indicated that …
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Charge Density Waves and Superconductivity in Rare Earth Compounds from First Principles
… conventional superconductors, strong electron-phonon coupling and high frequency phonons are the key ingredients to realizing this. However, strong electron-phonon coupling also leads to charge density waves and structural distortions which compete with superconductivity. To better understand …
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Optoelectronics of graphene-based Van der Waals heterostructures
… 2-4 are about hot electron dynamics and electron-phonon coupling in intrinsic graphene systems, among which Chapter 2 is focusing on the generation mechanism of the photocurrent at the p-n interface, which is demonstrated to have a photothermoelectric origin. This indicates a weak electron-phonon …
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Computational Studies of Correlated Electrons in One-Dimension
… spin-1/2 fermions and the inclusion of electron-phonon interactions in the Stochastic Series Expansion Quantum Monte Carlo method and the use of Quantum Parallel Tempering to improve the quality of the numerical data. For the extended Hubbard model at half-filling, we have confirmed the existence …
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Ab initio study of electron transport in lead telluride
… identify the importance to calculate electron-phonon interaction accurately. We then discuss the challenges in studying electron-phonon interaction in semiconductors using first-principles and introduce electron-phonon Wannier interpolation which allows us to calculate the strength of …
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Deconstructing the room-temperature emission spectra of nanocrystals using Photon-Correlation Fourier Spectroscopy
… spectral linewidth in terms of exciton-phonon coupling. Combined with a simple spectral lineshape model, we have worked towards quantitatively understanding exciton-phonon coupling with respect to specific nanocrystal structural and composition parameters.
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Understanding colloidal quantum dot excitation with solution photon correlation fourier spectroscopy
… This linewidth information is related to phonon coupling and gives insight into the separation of holes and electrons in excited CQDs. Experimental considerations and recommendations for troubleshooting a S-PCFS apparatus are also presented here.
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Thermal transport across transfer printed metal-dielectric interfaces: Influence of contact mechanics and nanoscale energy transport
… existing models that account for the electron-phonon non-equilibrium at the interface employ a phonon thermal conductivity that is difficult to estimate. We remove this difficulty by obtaining the conductance directly from the Bloch-Boltzmann-Peierls formula, describing the matrix element using …
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Transient extreme ultraviolet spectroscopy of semiconductors
… The distributions show rapid cooling by carrier-phonon coupling in the first few hundred fs followed by slow cooling due to the hot-phonon bottleneck effect for tens to hundreds of ps. The cooling dynamics differ, indicating that the electron-phonon and hole-phonon coupling pathways are …
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Studies in the theory of solids
… which is valid for all values of the electron-phonon coupling. When the electron-phonon coupling is strong, our result reduce to that of the well-known F~rster-Dexter theory. When the electron-phonon coupling is negligible, our results reduce to that of the two level model first considered by …
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Experimental investigations of excited-state dynamics in conjugated polymers using time-resolved laser spectroscopy
… and related systems. The properties of electron-phonon coupling in the conjugated polymer ladder-type methyl-substituted poly(para-phenylene) have been investigated using steady-state and picosecond fluorescence spectroscopy, with results demonstrating the thermal population of low energy …
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Investigation of the Photophysical Properties of pi-Conjugated Polymers. A Study by Non-Linear, Time-Resolved, and Single-Molecule Spectroscopy
… data the Debye-Waller factor, i.e. the electron-phonon coupling strength, was calculated and for MeLPPP a weak electron-phonon coupling was found at 1.5 K. Moreover, there is strong evidence that the low-frequency vibrational modes, which are coupled to the electronic transitions, stem from …
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Pressure dependence of spin fluctuations in metallic glasses Zrâ â Niâ â ,Zrâ â (Nix/Feâ â â -x)â â and /Zrx/feâ â â -x
… The volume (pressure) dependence of the electron-phonon coupling parameters Aep for CU25Zr75 was calculated using the McMillan equatio11. Using this volume dependence of Aep and the modified McMillan equation which incorporates spin-fluctuations, the volume dependence of the spin fluctuation …
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Many-Body Effects in the Thermodynamic Properties of Fermi Liquids and the Electron-Phonon System and in the Excitation Spectrum of Liquid Helium-4
… properties of Fermi liquids and of the electron-phonon system. Using normal liquid ('3)He as an example, I show that the T('3)lnT corrections due to spin fluctuations account for the finite temperature corrections to the leading term in the specific heat. I also calculate and compare the …
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Exciton Dynamics and Optical Properties of Lead Halide Perovskite Nanocrystals: From Nanorods to Nanocubes
… Additionally, dephasing mechanisms and coupling to phonons are not yet well understood in these semiconductors. In the first part of the thesis, I investigate highly confined, anisotropic CsPbBr3 nanorods, elucidating the photophysics governing their broad single-particle linewidths. I …
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AlGaN/GaN Dual Channel HFETs and Realization of GaN Devices on different substrates
… problems have been identified and solved. Hot phonon scattering is the bottleneck which limits the enhancement of electron velocity in the GaN 2DEG channel. It is found that the plasmon-phonon coupling is the mechanism for converting of hot phonons into high group velocity acoustic phonons. In …
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Spectroscopic Investigations of Light-Harvesting 2 Complexes from Rps. acidophila
… implied the existence of a different electron-phonon coupling strength for each complex, and moreover, led to the conclusion that at least for some of the complexes an exciton self-trapping process is effective. In a subsequent experiment, series of emission spectra from individual LH2 …
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Proximity effect in superconductors: Experimental and theoretical determination of the transition temperature
… lead-indium films, for which the strong electron-phonon coupling in lead might invalidate the theory. The experimental results are again in good agreement with the theory, showing that the strong-coupling effects are not large.
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