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Showing 1 to 20 of 20 for “"optical conductivity"”.
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A STUDY OF CERTAIN ELECTROMAGNETIC INTERACTIONS AMONG HIGH OPTICAL CONDUCTIVITY NANOSPHERES AND DIELECTRIC HALF-SPACES
<p>Electromagnetic coupling between a sphere and a semi-infinite substrate, and among several spheres present in the form of a composite were studied in this dissertation. Specifically, spheres made of noble metals such as Ag, Au and Cu and relatively high refractive index substrates and composite …
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Calculation of the optical conductivity for the Anderson impurity model using the slave boson technique
The optical conductivity of the Anderson impurity mode l has been calculated by emp l oying the slave boson technique and an expansion in powers of l i N, where N is the d egeneracy o f the f electron level . This method has been used to find the effective mass of the conduction electrons for …
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Interlayer optical response of yttrium barium (copper (cobalt, zinc)) oxide
We report optical reflectance and spectroscopic ellipsometry measurements of the in- and out-of-plane dielectric responses of chain substituted $\rm YBa\sb2Cu\sb3O\sb{6 + x}$ and $\rm YBa\sb2(Cu\sb{1 - y}Co\sb{y})\sb3O\sb{6 + x}$ and of plane substituted $\rm YBa\sb2(Cu\sb{1 - y}Zn\sb{y})\sb3O\sb{6 …
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Beyond particles and localities in quantum matters
… investigate include the fractional power-law in optical conductivity, the power-law liquid form of the scattering life-time, the violation of the conductivity sum rule, and the appearance of the anomalous dimension for the current. Our results suggest that the correct description of the …
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Far infrared reflectance and optical properties of organic superconductor (TMTSF)2ClO4 /
… analysis was carried out to determine the optical conductivity for the slowly cooled sample from the measured reflectance. In order to do so the low frequency data was extrapolated to zero frequency using a Hagen-Ru bens behaviour, and the high frequency data was extended with the data of …
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Understanding, constructing, and probing highly-entangled phases of quantum matter
… in doped semiconductors is explored, and optical conductivity is developed as an experimental tool to examine the nature of the QSL candidate Herbertsmithite. The material of this thesis is closely parallels that of Refs [1, 2, 3, 4, 5, 7,8, 9,10, 11].
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Theory of d₀ perovskites and their heterostructures
… interesting properties are two-dimensional superconductivity and ferromagnetism, sometimes concurrent. This study provides a starting point in understanding the reconstruction of bulk perovskite t₂[subscript g] bands near a surface or polar interface. First a symmetry constrained [k arrow] · [p …
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Carbon nanostructures/tin (IV) oxide systems and transparent electrode application
… was used to calculate a figure of merit, DC to optical conductivity ratio, from optical transmittance and sheet resistance. Among the metal alkoxides tested, tin isopropoxide was demonstrated to be the best dopant for carbon nanostructures, and carbon nanotube film and tin (IV) oxide system was …
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Large-shift Raman scattering in insulating cuprate materials
… A B1g feature coinciding in position with the optical conductivity peak is observed in all the T' phase materials, but not in the other insulators. An A1g peak is observed in Gd2Cu04 and Eu2Cu04 40-50 cm-1 lower in energy than the main A2g peak, and in YBa2Cu3Cu06 around 2400 cm-1 above the …
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Terahertz spectroscopy of quantum spin liquids
The optical properties of the spin-1/2 kagome lattice antiferromagnetic Herbertsmithite, ZnCu₃(OH)₆Cl₂, are studied by means of Terahertz Time-Domain Spectroscopy. Herbertsmithite is proposed to exhibit Quantum Spin Liquid behavior, in which electron spins have strong antiferromagnetic …
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Phenomenological phase-fluctuation model for the underdoped cuprates
… shown that the "violation" of the low-frequency optical sum rule recently observed in the SC state of underdoped Bi2212, which is associated with a reduction of kinetic energy, can be related to the role of phase fluctuations. The decrease in kinetic energy is due to the sharpening of the …
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Optical investigation of bismuth selenide (Bi2Se3) and antimony telluride (Sb2Te3).
… is devoted to the investigation of the optical properties of two topological insulators, Bismuth Selenide (Bi2Se3) and Antimony Telluride (Sb2Te3), by optical spectroscopy reflection measurements in a wide frequency range (500 – 40000 cm−1 ) and temperature (13 to 300 K) . Utilizing …
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Cluster Dynamical Mean-Field Theory: Applications to High-Tc Cuprates and to Quantum Chemistry
… such as Raman scattering intensity and optical conductivity, are computed for the two dimensional Hubbard model. The calculations include the vertex corrections which are essential to obtain physically reasonable results in interacting electron systems. We also study the physics of the …
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Low-dimensional purple and blue bronzes: Crystal growth, characterization and optical properties
… investigate the formation of the correct phase. Optical spectroscopy and electrical resistivity measurements were carried out on sodium purple bronze and potassium blue bronze. Sodium purple bronze crystals were found to exhibit a clear anisotropy in their natural cleavage (a-b) plane. Electrical …
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Holography for the practical person
… scaling for the mid-frequency regime of the optical conductivity and one that does not. We find no evidence for power-law scaling of the conductivity, thereby corroborating the previous negative result that gravitational crystals are insufficient to generate the power-law mid-infrared …
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Experimental consequences of mottness in high-temperature copper-oxide superconductors
… physics. In addition to the mechanism of superconductivity, understanding the properties of the normal state is a major puzzle in itself. As these materials are doped Mott insulators, the interaction between electrons is particularly strong. The strong electron correlations are responsible for …
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Normal and superconducting many-body systems
… temperature resistivity and a linear in 1/energy optical conductivity. The linearity of the scattering rate requires that the interacting Fermi liquid has strong peaks in its density of states (van-Hove singularities in 2 dimensions) near the chemical potential fl· Our results are backed by …
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Aspects of transport in strongly correlated systems with gravity duals
… usually possible. We study the dependence of the conductivity and the entanglement entropy on the space-time dimensionality in two different models of holographic superconductors: one dual to a quantum critical point with spontaneous symmetry breaking, and the other modelled by a charged scalar …
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Optical modeling off-stoichiometric amorphous Al2O3 thin films deposited by reactive sputtering
… brought up by previous research about how the optical properties of alumina droplets/particles found in solid rocket motors are related to their stoichiometry. We approached this question by adopting methods common in thin film technology. Alumina/aluminum/off-stoichiometric thin films were …
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Elektronen-Energieverlustspektroskopie von quasi-eindimensionalen Kupraten und Vanadaten
… The comparison of the experimentally determined optical conductivities and those derived from the bandstructrure calculations yield a good agreement upon adoption of an on-site Coulomb interaction U = 2-3 eV. In contrast to the strongly anisotropic hopping within the ladder plane the intersite …