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Showing 1 to 20 of 43 for “"dielectric function"”.
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Spectroscopic ellipsometry and dielectric modeling of thin film CdTe/CdS photovoltaic devices
… SE has seen use as a method for determining the dielectric function of each layer in heterostructured, thin-film photovoltaic devices. The aim of this thesis is to assess the capability of SE to resolve changes associated with illumination in the dielectric function of the absorbing layer of …
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The second and third order elastic constants of magnesium
… theory and c experiment. Both the Hartree dielectric function and a modified dielectric function were used; the results were found to be rather insensitive to whichever dielectric function is used. From a comparison of the calculated elastic constants with experiment, it was found that the …
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Quantum non-contact friction in resonant dielectric media
… force induced between two isotropic planar dielectric slabs which obey a plasma model dielectric function using scalar electromagnetism. All computations are carried out at zero temperature. Strong constraints on the integration parameters which define the friction force are derived and …
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Static and ultrafast optical properties of nanolayered composites : gold nanoparticles embedded in polyelectrolytes
… nm particles. The transient broadband complex dielectric function of a multilayer structure was determined experimentally by ultrafast pump-probe spectroscopy. This was achieved by simultaneous measurements of the changes in the reflectance and transmittance of the excited sample over a broad …
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Quantum-Based Modelling and Simulation of Materials Used In Small-Scaled Plasmonic Devices
… The dissipation of electromagnetic fields, dielectric function, electric field, and magnetic field are computed for various values of complex wave-vector. Additionally, a one-dimensional quantum-based frequency-dependent dielectric function for small-scale devices is investigated. A Rigorous …
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Optical dielectric properties of YBa2Cu3O6+x and Ba1-xKxBiO
… in polarization state can be calculated from the dielectric function of the surface and knowledge of the interface (roughness, geometry, surface layers, etc.). We have constructed a rotating analyzer ellipsometer (RAE) and modified it to allow measurement of samples significantly smaller than the …
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Regularization methods on solving Poisson’s equation and Poisson Boltzmann equation with singular charge sources and diffuse interfaces
… the fundamental solution with a space dependent dielectric function is intractable. In this research work, regularization formulations are introduced to capture the singularity analytically, which are the first of their kind for diffuse interface Poisson's equation and PB models. The success lies …
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The optical properties of bismuth nanowires
… which results from the spacial gradient of the dielectric function and the large dielectric mismatch between bismuth and the surrounding alumina or air. A comparison of the measured spectra with simulations of optical absorption resulting from direct L-point electronic transitions demonstrated …
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Properties of Nanoscale Biomaterials for Cancer Detection and Other Applications
… measurements enabled a calculation of the dielectric function and breakdown field strength of the ISAM films. The capacitance measurement technique was verified by measuring the dielectric function of a spin-coated thin film PMMA, which has a well characterized dielectric function [2]. …
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Optical and electrical properties of narrow gap germanium-tin alloys with high tin contents for middle and far infrared applications
… (0.190 – 6 µm). For the first time, the complex dielectric function, complex index of refraction, and absorption coefficient of GeSn alloys with atomic Sn percentages from 15- 27%, are presented. The characterization of the optical properties is important in itself for the development of novel …
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Polyelectrolyte multilayers for plasmonics and picosecond ultrasonics
… showed the shift of the LSP absorption peak as a function of the cover layer thickness of the particles. The data are modeled using an average dielectric function instead of the dielectric functions of air and polyelectrolytes. In addition using a measured dielectric function of the gold …
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Optical studies of highly-doped GaAs:C
… background. An effective-plasmon/one-phonon dielectric function with only two free parameters (plasma frequency ω<sub>p</sub> and damping constant γ<sub>p</sub>) gives a good description of the main features of the reflectivity spectra. The dependence of effective plasma frequency on hole …
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Plasmonic metamaterial for structural color printing and spontaneous emission control
… frequencies. The frequency-dependent complex dielectric function makes the metal property at optical frequencies behave totally different with that at other spectral ranges with lower frequency such as infrared and microwaves. This novel property makes the so called plasmonics or …
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Field Theory of Mottness
… 2e bosonic field. We also calculate the inverse dielectric function and show that it possesses a sharp quasiparticle peak and a broad particle-hole continuum. The sharp peak is mediated by a new charge e composite excitation formed from the binding of a charge 2e boson and a hole and represents a …
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Impurities in Antiferromagnetic Transition-metal Oxides – Symmetry and Optical Transitions
… state Hamiltonian, calculated within Density Functional Theory. The frequency-dependent complex dielectric function is calculated within the Independent Particle Approximation, and optical transitions are evaluated in multiple different ways. Peaks in the imaginary part of the dielectric …
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Magnetic and thermal properties of metallic antiferromagnetic materials
… heat capacity, as expected if the changes in dielectric function are dominated by contributions of exchange interactions to the dielectric function. In spintronic devices, it is essential to determine the dynamics of magnetic precession, the frequency of spin waves, the thermal stability of …
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Studies on structural, electronic and optical properties of SnO2 doped with nitrogen, chloeine, antimony and indium
… the current theoretical study used Density Functional Theory (DFT) calculations of different metal and nonmetals (N, Cl, In, and Sb) and (N-Cl and In-Sb) as dopants and co-dopants, respectively. The results show that due to the band gap narrowing and the existence of impurity levels in the …
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Model for an exciton mechanism of superconductivity in planar geometry
… derive these results in terms of the microscopic dielectric function is also given~ A calculation of what superconducting transition temperatures one could expect to see due to this effect follows, both for the case of the exciton mechanism acting alone; and for the case of the exciton mechanism …
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Theory of terahertz intervalence band polaritons and antipolaritons.
… and antipolaritons. The approach is based on the dielectric function formalism. The dielectric constant is derived from an optical susceptibility evaluated with Non Equilibrium Many Body Green's Functions (NEGF), which is then adjusted to a Lorentzian fit. Finally, the resulting expression is …
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Characterization of OMVPE-grown GaSb-based epilayers using in situ reflectance and ex situ TEM
… calibrations was also demonstrated. Analytic functions were used to model the refractive indices of GaSb, AlGaAsSb, and GaInAsSb. Specifically, Adachi's Model Dielectric Function [1, 2] was curve-fit to data for GaSb between 400 and 1000 nm, and fourth-order polynomials were fit to data for …
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