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 24 for “"Non-Fermi liquid"”.
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The Death of Quasiparticles: Strongly Interacting Gapless Phases with Fermi Surfaces and Fractional Statistics
… interactions and two additional ingredients – Fermi surfaces and fractional statistics. Chapter 2 through Chapter 5 focus on strongly interacting metals with Fermi surfaces. The most salient examples are a class of Hertz-Millis models describing the onset of spontaneous symmetry breaking in a …
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Field-induced magnetic phase transitions and correlated electronic states in the hexagonal RAgGe and RPtIn series
… Moreover, a large number of Ce-based heavy fermion compounds have been studied, whereas the analogous Yb-based ones are much rarer. We thus wanted to study local moment metamagnetism and Yb-based heavy fermion physics in hexagonal systems.;The RAgGe and RPtIn series belonging to the Fe2P …
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Pressure Induced Quantum Phase Transitions in Metallics Oxides and Pnictides
… FeCrAs is a ternary metal pnictide with Fermi liquid specific heat and susceptibility behaviour but non-metallic non-Fermi liquid resistivity behaviour. Characteristic properties of the compound are explained and compared to those of superconducting pnictides. Antiferromagnetic (AFM) …
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Spin liquids : mean field and beyond
Spin liquids are fluid-like ground states of spin systems, where spins do not order at zero temperature. These states have long-range entanglement and concomitant exotic properties, such as fractionalized excitations and emergent gauge field. In this thesis we use mean field approach and its …
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Aspects of quantum criticality in itinerant electron ferromagnetic systems
Fermi-liquid theory is one of the standard models of condensed matter physics, supplying a valid explanation of the low temperature properties of many metals. However, non-Fermi-liquid behaviours arise in many itinerant systems that exhibit a zero temperature magnetic phase transition. This thesis …
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Exotic Phenomena Emerging from Localized Multipolar Degrees of Freedom
… group methods, we uncover a number of stable non-Fermi liquid ground states. We next examine the nature of these fixed points using boundary conformal field theory techniques, to provide a non-perturbative description of their transport and thermodynamic properties. We then consider the …
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Screening and the effective fine structure constant in graphene
… but evidence of strong-correlation effects and non-Fermi liquid behavior remains limited. We describe a method to probe the strength of these interactions, characterized by an effective fine-structure constant α∗(q, ω), as measured with inelastic x-ray scattering (IXS) on graphite. We show how …
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Search, Discovery, Synthesis and Characterization of Itinerant Magnets Composed of Non-magnetic Constituents
… phenomena that frequently accompany it: heavy fermion behavior, coexistence of superconductivity and magnetism, metamagnetic transitions, spin- and cluster-glass behavior, multisublattice magnetism, non-Fermi liquid behavior, and quantum criticality. Surprisingly, while many systems exhibit …
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Defect-induced magnetism and transport phenomena in epitaxial oxides
… conduction modes, with tendencies towards non-Fermi-liquid behaviour observed in certain two-dimensionally conducting samples in limited temperature regimes. By optimising the (defect) structure at the interface, i.e. by introducing a single unit cell of (La0.5,Sr0.5)TiO3 or SnTiO3, it is …
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Unconventional Superconductivity in the Layered Iron Germanide YFe2Ge2
… dependence, which is an indication of non-Fermi-liquid behaviour. While superconductivity in YFe$_2$Ge$_2$ has been widely observed below $T_c \approx \SI{1.9}{\kelvin}$ in electric transport measurements, evidence of a bulk superconducting transition has proved elusive. This has …
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Magnetic and Structural Instabilities in Cerium Diantimonides under Pressure
… onset of unconventional superconductivity and non-Fermi liquid behaviour at a quantum critical point at pc ≃ 32 kbar. A comprehensive series of high-pressure measurements have been employed to track the development of this structural transition, determine the high-pressure crystal structure and …
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An Investigation of the Magnetic and Electrical Properties of YNi3
… to solidstate research because they demonstrate non-Fermi-Liquid behaviour and allow us to probe the quantum nature of the solid state in magnetic materials. Spin fluctuation theory is currentlythe most successful tool we have for trying to describe critical behaviour on the border of magnetism, …
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Strong correlations and topological order in one-dimensional systems
… as well as topologically ordered systems in 1D. Non-Fermi liquid behavior characteristic of interacting 1D electron systems is investigated with an emphasis on experimentally relevant setups and observables. The existence of end Majorana fermions in a 1D p-wave superconductor subject to periodic, …
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Pressure Tuned Magnetism in d- and f-Electron Materials
… new states of matter, for example; the marginal Fermi Liquid and non Fermi Liquid states as well high T$_C$ cuprate and magnetically mediated superconductivity. In this thesis I present work on three materials in which it may be possible to tune the system through a magnetic QPT with the …
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Electromagnetic response of time-reversal breaking metallic phases in two dimensions
… they are parallel. This beta phase exhibits nonvanishing un-quantized anomalous Hall effect in the absence of external magnetic fields, which corresponds to the Berry curvature on the Fermi surface. The alpha phase does not have that property. To go beyond the mean-field, we introduce the …
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Correlated low temperature states of YFe2Ge2 and pressure metallised NiS2
… Existence of the latter is also indicated by the non-Fermi liquid T$^{3/2}$ behaviour of the low temperature resistivity. Below 1.8 K a superconducting phase develops in the material, making it a rare case of a non-pnictide and non-chalcogenide iron based superconductor with the 1-2-2 structure. …
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Cooling an electron gas using quantum dot based electronic refrigeration
… are made by cooling the sample to 1.5 K with liquid Helium-4, to 300 mK with liquid Helium-3, or even down to a few mK using a dilution refrigerator. However, at lower temperatures the electron gas becomes increasingly decoupled from the lattice in which it resides. Below ~ 1 K the coupling …
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Magnetic, thermodynamic and transport properties of the magnetic semiconductor Fe₁₋xCoxS₂ and superconducting LaSb₂
In recent years magnetic semiconductors have attracted a great deal of attention because it is thought that they can be used to generate spin polarized current in spintronics, an emerging field where the spin degree of freedom of charge carriers is utilized in microelectronic devices. In this …
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Non-perturbative approaches to strongly correlated electron systems
… strongly correlated electron systems requires a non-perturbative analysis because Fermi liquid theory inevitably breaks down due to the strong correlation. In this thesis, we will study two non-perturbative approaches to tackle strongly correlated electronic system: 1.) multi-dimensional …
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Holography and strongly correlated systems
… Away from the low frequency limit we find a nontrivial radial flow from the black hole horizon to the boundary of the spacetime; we derive equations governing this flow and demonstrate their use in the simple examples of charge and momentum diffusion. Next, we turn to the study of strongly …
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