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 27 for “"Lattice distortion"”.
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Strain and lattice distortion in semiconductor structures : a synchrotron radiation study
Die Arbeit stellt neu entwickelte Röntgenbeugungsmethoden vor, mit deren Hilfe der Verzerrungszustand des Kristallgitters von Halbleiter-Wafern und -Bauteilen im Detail charakterisiert werden kann. Hierzu werden die aussergewöhnlichen Eigenschaften der an modernen Synchrotrons wie der ESRF …
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Determination of local crystal symmetry in complex, multielement, ferroelectric perovskites and alloys
Structural change arising from correlated lattice and charge interaction in complex, multi-element, crystals has a profound effect on their physical properties. Examples include charge ordering in complex oxides, polarization nanodomains in ferroelectrics, and vortex matter. A common scheme to …
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Vortex Lattices in Rapidly Rotating Bose -Einstein Condensates: Modes, Elasticity, and Melting
"We approach the static elasticity of a vortex lattice using the elastohydrodyamic approach. We derive the elastic Green's function for the vortex lattice, and connect it to the lattice distortion in an inhomogeneous condensate. We find that the longitudinal elastic response of a vortex lattice is …
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Investigating Chemical and Structural Heterogeneities of High-Voltage Spinel Cathode Material for Li-ion Batteries
… We develop a method to measure and relate lattice strain to phase distribution at the tens of nanometers scale. In Chapter 3, mapping lattice distortions of LNMO particles with varying global Mn oxidation states reveals inherent structural defects and distortion heterogeneities. In Chapter …
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DESIGN AND SYNTHESIS OF FERROIC HYBRID ORGANIC-INORGANIC PEROVSKITES
… perovskites afford highly versatile lattice dimensionalities, establishing them as novel material paradigms for the tailoring of ferroic behaviors. This flexibility allows for the modification of symmetry through lattice distortion or chirality transfer, thereby enabling the …
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Characterization of phase transitions by the analysis of crystal structures
… From the omega-2theta maps the monoclinic lattice distortion of the low-temperature phase of CrOCl was determined.
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Elucidation of Charge Density Wave Stability and Defect Interactions in the Highly-Ordered Structural Transition Metal Dichalcogenide System 1T-TaS2
… correlated state between electron density and lattice distortion, originally predicted to only exist in one dimension. The discovery of CDWs in two-dimensional systems spiked interest in uncovering the various phases and phase interactions. Understanding the phase interactions is of fundamental …
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Origins and implications of intrinsic stress in hydrogenated amorphous silicon thin films
… causing of peening the film, and leading to lattice distortion in the material. Conversely, tensile stress is created through bombarding ions collapsing nano-sized voids within the material, which are formed during the vapor-phase deposition. Combining our model of ion momentum with the …
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Synthesis of 1T-Tantalum (IV) Sulfide and observation of charge density wave using scanning tunneling microscopy
… density. Unlike bulk semiconductor or metals, lattice distortion in this low-dimensional material creates non-uniform, wave-like electron densities. In this thesis, we have demonstrated two bulk material growth strategies for the synthesis of 1T-TaS2. We have successfully grown poly-crystalline …
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Growth by radio frequency sputtering and characterisation of rare earth doped wide bandgap oxides
… anatase to rutile, internal strain building and lattice distortion due to Nd3+ incorporation in titania, correlated with optical changes, were evidenced. Exciting titania and zinc oxide matrices with optimal Nd concentrations, with ultra-violet (UV) light energies equal to or above their gap …
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Synchrotron radiation-based characterization of GaN- based MQW structures and strongly correlated materials
… The results demonstrated the importance of lattice distortion symmetry at the phase boundaries as a means for the coherent coexistence of two domain types within the film volume. Synchrotron-based far-infrared spectroscopy was performed at low temperatures on the single crystal multiferroic …
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Chemical selection rules of single-phase high-entropy oxides
… the same polyhedral sites, introducing severe lattice distortion throughout a structure. However, the mechanism of chemical selection rules for designing new high-entropy oxides was still unclear. Randomly mixed, multi-components usually form composites instead of a single-phase, solid …
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Twist error response of periodic lattices to strain energy distribution
Periodic lattices, when used as assembly scaffolds, can augment pre-existing 2D manufacturing techniques to fabricate 3D structures with heterogeneous materials, components and architecture such as human organs for transplant patients, and micro batteries. Periodic lattices are first preformed and …
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Preparation and characterization of doped lead zirconate titanate Pb(Zr<sub>x</sub>Ti<sub>1-x</sub>)O₃ films
… in terms of the Curie temperature, crystal distortion, transformation temperature, microstructure, optical properties, and electrical properties. In addition to the dopant effect, the effects of substrates were also investigated with regard to crystallization and preferred orientation. The …
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Synthesis of lithium manganese phosphate by controlled sol-gel method and design of all solid state lithium ion batteries
… organic liquid electrolyte due to Jahn-Teller Lattice distortion. This problem was tried to endorse in this thesis. In the second chapter by synthesizing nano sized cathode particles with good electronic conductivity, good performance was achieved. In the third chapter additive olivine cathode …
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A search for superconductivity in conjugated polymers
… discrete tight-binding electron-lattice model which incorporates on-site and nearest-neighbour electron-electron Hubbard terms, Brazovskii-Kirova symmetry breaking, and Kondo impurities. We have found that through changing the conduction charge doping level real space-charge …
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Modeling of Effect of Alloying Elements on Radiation Damage in Metallic Alloys
… introduce both global volume expansion and local lattice distortion in the Fe matrix. In order to understand how oversized W influences the defect production behaviors in Fe-based alloys, molecular dynamics simulations were conducted to study the primary damage in three systems at 300 K: (a) …
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Use of diffusion multiples to explore the Co-Cr-Fe-Mn-Ni high entropy system, The
… nano-hardness maps did not support the severe lattice distortion hypothesis proposed for HEAs, a comparison of different solid solution strengthening mechanisms suggests that elastic modulus mismatch and a change in the lattice friction stress were the most likely contributors to strengthening.
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The Gutzwiller variational method for strongly correlated systems
… accepted theoretical picture for vanishing lattice distortion as the metallic state emerges, the JT distortion survives even beyond the transition pressure into the metallic region and 2) the application of pressure leads to a structural phase separation and breaks the material into two …
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Operando Optical Tracking of Ion Dynamics and Degradation in Battery Electrodes
… orientations associated with the monoclinic lattice distortion at Li₀.₅CoO₂. Secondly, we employ optical scattering microscopy to examine state-of-the-art Ni-rich layered oxide cathodes. Here, a continuous change in scattering intensity with state-of-charge (SOC) enables direct observation of …
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