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 49 for “"Metal insulator transition"”.
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Metal-insulator transition in yttrium- and neodymium-doped lanthanum nickelates
… to have a rich structural phase diagram and a metal-insulator transition T [subscript M−I] that varies based on the rare-earth element. This work investigates steric and doping effects in bulk nickelates La₁₋ₓRₓNiO₃ (R = Y, Nd) and both develops and tests the prediction of a universal T → 0 …
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Percolation and nanosecond fluctuators in V2O3 films within the metal-insulator transition
… sesquioxide (V2O3) exhibits a first-order metal-insulator transition (MIT) at 160 K between a low temperature, monoclinic, antiferromagnetic Mott insulator and a high temperature, rhombohedral, paramagnetic, metallic phase. In thin films, due to strain, the transition takes place over a …
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Thermodynamics of disordered C1-xCux and Si1-xAux near the metal-insulator transition
… of disordered, interacting electrons near the metal-insulator transition.
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Character of the Electronic States Near the Metal -Insulator Transition in Gallium Manganese Arsenide
… of electronic states near the Mott-Anderson metal-insulator transition in the ferromagnetic semiconductor Ga1-xMn xAs is studied by cross sectional scanning tunneling microscopy. 200nm thick samples grown by MBE at UCSB with doping levels from 1.5%, close the metal-insulator transition, to …
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Character of the electronic states near the metal-insulator transition in Gallium Manganese Arsenide
… of electronic states near the Mott-Anderson metal-insulator transition in the ferromagnetic semiconductor Ga1-xMnxAs is studied by cross sectional scanning tunneling microscopy. 200nm thick samples grown by MBE at UCSB with doping levels from 1.5%, close the metal-insulator transition, to 5%, …
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Spin-orbit scattering and E-field effects in discordered metals near the metal-insulator transition
The results of two studies of disordered metals near their metal-insulator transition are presented: (i) A detailed comparison of GexAu1-x and BxCu1-x is carried out in zero magnetic field. GeAu, a high Z material, has been shown to e xh1bit strong spin-orbit effects in a magnetic field while 8Cu, …
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Spin-Orbit Scattering and E-Field Effects in Disordered Metals Near the Metal-Insulator Transition (Amorphous Conductors)
The results of two studies of disordered metals near their metal-insulator transition are presented: (i) A detailed comparison of Ge(,x)Au(,1-x) and B(,x)Cu(,1-x) is carried out in zero magnetic field. GeAu, a high Z material, has been shown to exhibit strong spin-orbit effects in a magnetic field …
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Thermodynamics of disordered carbon(1-x)copper(x) and silicon(1-x)gold(x) near the metal-insulator transition
Measurements of the electron-phonon relaxation time are carried out, using both a direct and indirect method, in three dimensional films of C$\sb{1-x}$Cu$\sb x$ and Si$\sb{1-x}$Au$\sb x$ in the temperature range 0.3K-4K. The electron-phonon resistance and thermal boundary resistance are also …
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Complex Phase Behavior of Exotic Oxides: Optical Spectroscopy Studies
We observed that the metal-insulator transition in Ca3Ru 2O7 is characterized by the opening of correlation charge gap. The out-of-phase c-axis oxygen vibration phonon mode is seen to be closely associated with the metal-insulator transition possibly by modulating the bandwidth of the system. We …
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Determination of the liquid-gas phase diagram for electrons and holes in germanium
… diagram and critical point of the liquid-gas transition have been determined. The position of the metal-insulator transition has been estimated. The electron-hole 1iquid-EHG-exciton system was investigated spectroscopically with particular attention paid to the liquid-gas critica1 region. …
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Complex phase behavior of exotic oxides: optical spectroscopy studies
… ellipsometry, to study complex phase transition behavior exhibited by the doped rare-earth manganese oxides, R1_xDxMn03 (0 :::; x :::; 1), and the layered calcium ruthenium oxide, Ca3Ru20 7 , in which there exist strong correlations among charge, lattice, spin, and/or orbital degrees …
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Correlations in the one-dimensional Hubbard model
… induces a gap in the excitation spectrum and a metal-insulator transition is predicted as the Coulomb repulsion parameter is changed.
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First principles quantum Monte Carlo study of correlated electronic systems
… fractional quantum Hall effect, and Mott insulator. Strongly correlated systems have been an important subject of condensed matter physics for several decades, especially after the discovery of high temperature cuprate superconductors. In this thesis, we apply first principles quantum …
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MOMENTUM SIGNATURES OF THE ANDERSON TRANSITION
… of Anderson localization and the Anderson metal-insulator transition (MIT) in momentum space. We find that an initial plane-wave propagating in a disordered medium exhibits a diffusive background and two interference peaks, the coherent backscattering (CBS) and the coherent forward …
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Tailoring charge to spin conversion in novel materials for efficient spintronics
… conversion efficiency (by more than 5X) via the metal-insulator transition in a quintessential strongly correlated electron compound vanadium dioxide (VO₂). We then show that by engineering the chemical order in the newly discovered magnetic Weyl semimetal (MWSM), Co₂MnGa, we can control the …
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Understanding the viability of impurity-band photovoltaics : a case study of S-doped Si
… the sulfur concentration is increased across the metal-insulator transition, and how the electronic structure is linked to the anomalously high subband gap absorption. A discrete change in local electronic structure is seen that corresponds to the macroscopic change in electronic behavior. …
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Materials and devices for optical switching and modulation of photonic integrated circuits
… is and 1 mW operating power were demonstrated. A metal-insulator transition material, V02, was identified as a material with potential for enhancing the switch speed with speeds in excess of gigahertz rates with minimal device footprint. Fundamental material transport properties and …
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Understanding, constructing, and probing highly-entangled phases of quantum matter
… the role of interactions in electron topological insulators (TIs). Non-perturbative definitions of the familiar topological band-insulator are given, and new strongly-correlated TIs with no band-structure analogs are identified. The last Part turns exotic gapless phases without quasi-particle …
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Study of localization and correlation effects in disordered electronic systems
… or in combination, such features as the metal-insulator transition, response functions like the frequencydependent conductivity and the magnetic susceptibility, and diffusion of charge-and spin-density fluctuations, for example. We have also investigated the effects of localization in the …
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Computational Study of Carbon-Based Low-Dimensional Materials on Structures, Properties and Applications
… extreme mechanical performance and intriguing metal-insulator transition under tension has been demonstrated. The properties of proposed 1D boron nanostructures have also been investigated and a constant-tension structural transition between two boron phases has been revealed. Secondly, two …
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