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 20 for “"Strongly correlated materials"”.
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Synchrotron radiation-based characterization of GaN- based MQW structures and strongly correlated materials
The following dissertation applies synchrotron radiation-based characterization techniques to the fields of gallium nitrides, multiferroic manganites, and self-assembled nano-domain oxide films. These material systems were chosen due to their unusual properties and potential device applications, …
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X-ray scattering studies of strongly correlated materials: orbital ordering in KCuF3 and stripe-like domain structures in BiFeO3 epitaxial thin films
The results of x-ray scattering experiments on orbitally ordered KCuF3 and periodic arrays of stripe-like ferroelectric domains in epitaxial thin films of multiferroic BiFeO3 are presented in this dissertation. Both resonant soft x-ray elastic scattering and non-resonant hard x-ray elastic …
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Magnetic-field- and pressure-tuned phases in LaxPryCa1−x−yMnO3 and Mn3O4: inelastic light scattering studies and single crystal growth
… I present our studies on two distinct strongly correlated materials: the manganese perovskites LaxPryCa1−x−yMnO3; and the manganese-based spinel Mn3O4. For this study, Raman (inelastic light) scattering spectroscopy was used as a main experimental technique because Raman scattering can …
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Collective modes in strongly correlated electron systems measured with momentum-resolved electron energy-loss spectroscopy
"Strongly correlated electron systems comprise an exciting area of research in condensed matter physics due to the variety of quantum phenomena that results from the strong interactions between the electrons. Strongly correlated materials can be described in terms of weakly interacting, emergent …
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Ultrafast Terahertz Spectroscopy for the Manipulation and Elucidation of Correlated Quantum Materials
… of, or controlling various aspects of quantum materials, a class of materials whose macroscopic properties are only understood through quantum mechanics. Quantum materials are often categorized into two classes: topological materials or strongly correlated materials, though the cross-over and …
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Beyond particles and localities in quantum matters
Many properties of strongly correlated materials behave differently from those obeying the standard theory of metals. Explaining such anomalous properties may require one to consider a non-traditional model. In this dissertation, we construct several phenomenological models based on the notions of …
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Projector Quantum Monte Carlo Methods for Linear and Non-linear Wavefunction Ansatzes
… wavefunction ansatzes and its application to strongly correlated materials. This new approach is partially inspired by a prior application of the Full Configuration Interaction Quantum Monte Carlo (FCIQMC) method to the three-band ($p-d$) Hubbard model. Through repeated stochastic application …
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Ultrafast Terahertz Spectroscopy of Collective Excitations in Correlated Materials
Strongly correlated materials exhibit a multitude of exotic phases of matter. Originating from strong interactions between electrons, the properties of these systems are governed by a delicate balance among the lattice, charge, orbital, and spin degrees of freedom, leading to complex ground state …
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Imaging magnetic order in magneto-structural phases of Mn3O4
… of similar phase separation behaviors in related strongly correlated materials.
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Computational modelling of the electronic and structural properties of chalcopyrite-type semiconductors and platinum group metal chalcogenides
… for use in photovoltaic systems is the design of materials with appropriate band gaps. Electronic structure calculations based on Density Functional Theory (DFT) have been extensively used to study and to describe such properties of many condensed matter systems. In this work, we have utilized DFT …
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Wigner crystallization in moiré materials
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2022-11-11 without embargo terms
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The Study of Transition Metal Oxides using Dynamical Mean Field Theory
… the on-site interaction, electrons are much more correlated and cannot be described using traditional one-electron picture, thus the name "strongly correlated systems". With strong correlation, there exists a variety of interesting phenomena in these systems that attract long-standing interests …
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High magnetic field study of strongly correlated electron systems
The physics of strongly correlated electron systems is remarkably rich and complex with the interactions between electrons giving rise to a diverse range of physical phenomena including ferromagnetism, metal-insulator transition and superconductivity. Observation of quantum oscillations in the …
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Phases and phase transitions of strongly correlated electron systems
Different experiments on strongly correlated materials have shown phenomena which are not consistent with our conventional understandings. We still do not have a general framework to explain these properties. Developing such a general framework is much beyond the scope of this thesis, but here we …
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Inelastic light scattering studies of quantum phase transitions in CuxTiSe2 and multiferroic TbMnO3
… magnetic-field-induced phase transitions of two strongly correlated systems – the magnetoelectric multiferroic TbMnO3 and the layered dichalcogenide TiSe2 . In general, strongly correlated materials have a strong coupling between charge, spin, lattice and orbital degrees of freedom. Because of …
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Hubbard-corrected density functional theory : sensitivity to projection-space and renormalization of Coulomb interaction.
… has become a widely used framework for modeling materials in which localized d or f electrons give rise to strong electronic correlations. By introducing an explicit on-site Coulomb interaction, DFT+U can substantially improve the description of electronic structure, lattice properties, and phase …
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Mocking quantum mechanics: Semiclassical and machine-learning approaches to frustrated magnetism
… wave functions makes direct simulation of large, strongly interacting quantum systems impossible, and necessitates strategies to manage the complexity in an analytically or computationally tractable manner. The bulk of this thesis explores two such strategies in the context of quantum spin …
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Unconventional Fermi surface in insulating SmB6 and superconducting YBa2Cu3O6+x probed by high magnetic fields
… beyond the traditional description in these strongly correlated electronic systems. SmB$_6$ is a classic example of Kondo insulators whose insulating behaviour arises due to strong correlation between the itinerant $d$-electrons and localised $f$-electrons. The peculiar resistivity plateau …
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The electronic structure of the pair-density-wave (PDW) superconductor in the cuprates
… existence of PDW superconducting order in many strongly correlated materials in the absence of any external magnetic field, particularly in the cuprate superconductors. A crucial feature of the PDW state that reconciles certain aspects of the cuprates phenomenology is that inherently it has a …
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Multipoles, Magnetic charges and chiral properties in antiferromagnetic materials inferred from resonant X-Ray diffraction
… features behind the exotic orderings of materials have attracted the attention of many scientists. This new physics can be related to the magnetic and charge multipoles defined by a few electrons around the atomic core in the valence states. The uses of x-rays and neutrons techniques, due …