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 78 for “"electron systems"”.
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Magnetism in strongly correlated electron systems
… examples of magnetism in strongly correlated electron systems, the high-T$\sb{c}$ materials and heavy fermions.
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The study of many-electron systems
… and approximation schemes are used to study many-electron interacting systems. Two important many-particle models, the Anderson model and the Hubbard model, and their electromagnetic properties have been investigated in many parameter regimes, and applied to physical systems. An Anderson …
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Spectral properties of strongly correlated electron systems
… of the cluster-perturbation theory (CPT) to systems with spontaneous broken symmetry. Our method accounts for both short-range correlations and long-range order. Short-range correlations are accurately taken into account via the exact diagonalization of finite clusters. Long-range order is …
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Frustrated Magnetism in Strongly Correlated Electron Systems
… excitations in several strongly correlated electron systems, where exotic orderings can be induced as a result of magnetic frustration and quantum fluctuations. We show that emergent spin textures can arise close to a magnetic field-induced quantum critical point, when the single magnon …
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Phonon Spectroscopy and Low-Dimensional Electron Systems
… about the properties of low-dimensional electron systems, but in order to interpret the experiments and to understand the underlying physics, a comparison with theoretical models is absolutely necessary. A central point of this work is therefore a universal theoretical approach allowing …
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Anistropic phenomena in strongly correlated electron systems
… with momentum anisotropy in strongly correlated electron systems, and explores its origin and its consequences through two contrasting projects. The first is a study of the temperature dependences of magnetotransport quantities in the normal state of the cuprate high-temperature superconductors. …
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Renormalization-group theory of correlated electron systems
… theory to a variety of correlated electron systems, determining finite-temperature phase diagrams and thermodynamic properties for electron densities both at and away from half-filling. We begin by assessing the effectiveness of the Suzuki-Takano quantum decimation method on a d = 1 …
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Theoretical study of interacting low dimensional electron systems
This thesis addresses the question of a strongly interacting many-body problem: the Hubbard model on one- and two-dimensional lattices. The technique employed is the small-cluster method wherein the full many-body Hamiltonian for finite clusters with periodic boundary conditions (PBC's) is solved …
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Non-perturbative approaches to strongly correlated electron systems
"Strong electron correlation phenomena are ubiquitous, such as unconventional superconductivity and the metal-insulator transitions. Having a proper understanding of strongly correlated electron systems requires a non-perturbative analysis because Fermi liquid theory inevitably breaks down due to …
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Field theoretical methods for strongly correlated electron systems
… computational tool to study quantum many-body systems. They have been applied successfully to the study of various systems of strongly correlated electrons in condensed matter physics, particularly to problems where a non-perturbative treatment is required.
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Field theoretical methods for strongly correlated electron systems
… computational tool to study quantum many-body systems. They have been applied successfully to the study of various systems of strongly correlated electrons in condensed matter physics, particularly to problems where a non-perturbative treatment is required. In the first part of this thesis we …
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Spectroscopy of Two Dimensional Electron Systems Comprising Exotic Quasiparticles
… collective states emerging from interactions in electron systems confined to two dimensions. These studies span the first, second and third Landau levels. I report for the first time, high energy excitations of composite fermions in the quantum fluid at v = 1/3. The high energies discovered …
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Angle-resolved photoemission studies of two-dimensional electron systems
This dissertation examines the electronic properties of 2D electron systems, including ultrathin metallic films grown on semiconductor substrates and graphite/graphene layers. Both systems are (quasi) two-dimensional and are of particular interest due to their technological importance. The major …
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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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Interaction effects and disorder in two-dimensional electron systems
… in the localised regime of two-dimensional electron systems (2DES) with varying disorder. Devices with dimensions of a few microns were fabricated from modulation doped GaAs/ AlGaAs heterostructures, where the strength of disorder was tuned by changing the width of the undoped spacer layer …
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Phases and phase transitions of strongly correlated electron systems
… We try to track such phenomena in heavy fermion systems, which are correlated fermi liquids. In these systems, a lattice of localized electrons in f or d orbitals is coupled to the conduction electrons through an antiferromagnetic coupling. Singlets are formed between localized and conduction …
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HYDRODYNAMIC AND BALLISTIC TRANSPORT IN ULTRA-CLEAN 2D ELECTRON SYSTEMS
… broadly on hydrodynamic transport in mesoscopic systems, resulting from strong electron-electron interactions. In the first part, we consider electrons are in near thermal equilibrium with each other, and for which case we calculate conductance by solving hydrodynamic equations. We do this for …
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Low-dimensional electron systems fabricated with an atomic force microscope
… there has been intensive research into electron transport in low dimensional systems, especially those fabricated in semiconductor material. This research has added to our understanding of electrical transport properties outside of the macroscopic regime, and allowed exploration of …
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