Sökning: "quantum Hall effect"
Visar resultat 21 - 25 av 37 avhandlingar innehållade orden quantum Hall effect.
21. Engineering Epitaxial Graphene for Quantum Metrology
Sammanfattning : Quantum resistance metrology deals both with the precise and accurate measurement of electrical resistance, by utilizing the quantum hall effect (QHE) in two-dimensional electron gases (2DEGs) such as those based on gallium arsenide (GaAs). Due to the unique properties of graphene, and specifically epitaxial graphene grown on silicon carbide (SiC/G), quantum Hall resistance (QHR) standards based on graphene perform better in a wider parameter space (temperature, current and magnetic field) than conventional semiconducting materials. LÄS MER
22. Enabling technologies for scalable graphene electronics
Sammanfattning : This thesis addresses the challenges in scaling up graphene-based technologies, with a focus on the epitaxial growth of graphene (epigraphene) over SiC substrates and the establishment of reliable low-contact resistance electrical contacts. The scalable graphene growth and contact fabrication have enabled the development of three epigraphene-based devices, including large-scale Quantum Hall Arrays, highly sensitive Hall effect magnetometers with minimal noise, and quantum-limited ultraviolet (UV) detectors. LÄS MER
23. Topics in Five Dimensional Supersymmetry and Topological Quantum Field Theories
Sammanfattning : We explore five-dimensional supersymmetric quantum field theories and topological quantum field theories. In five dimensions, we describe a framework to consistently define a supersymmetric theory on a curved spacetime manifold. LÄS MER
24. Molecular Doping of Epigraphene for Device Applications
Sammanfattning : Epitaxial graphene grown on silicon carbide, or epigraphene, offers in principle a suitable platform for electronic applications of graphene which require scalable, reproducible, and high-quality material. However, one of the main drawbacks of epigraphene lies in the difficulty in controlling its carrier density, which hinders its usefulness in future applications. LÄS MER
25. Topological Phase Transitions in Magnetic Nanostructures of Dirac Materials
Sammanfattning : Over the past two decades, the discovery of topological Dirac materials, such as topological insulators and semimetals, has defined a new paradigm in condensed matter physics and established new platforms for realizing spin electronic devices and quantum computing. The novel quantum properties of these materials, which are mainly due to the presence of strong spin-orbit coupling, are invariant under topological transformations, making them more resilient to structural disorder, electromagnetic and thermal fluctuations in comparison to the conventional silicon-based materials. LÄS MER