Search for dissertations about: "quantum Hall effect"

Showing result 21 - 25 of 37 swedish dissertations containing the words quantum Hall effect.

  2. 21. Engineering Epitaxial Graphene for Quantum Metrology

    Author : Hans He; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Epitaxial Graphene; Magnetotransport; Quantum Resistance Metrology; Chemical Doping;

    Abstract : 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. READ MORE

  4. 22. Enabling technologies for scalable graphene electronics

    Author : Naveen Shetty; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; edge contact; Hall effect; graphene; 2d-tech; array; 1 f; metrology;

    Abstract : 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. READ MORE

  5. 23. Topics in Five Dimensional Supersymmetry and Topological Quantum Field Theories

    Author : Luigi Tizzano; Maxim Zabzine; Anton Kapustin; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Supersymmetric Quantum Field Theories; Topological Quantum Field Theories; String Theory.;

    Abstract : 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. READ MORE

  6. 24. Molecular Doping of Epigraphene for Device Applications

    Author : Hans He; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Molecular Doping; Graphene; epitaxial graphene; THz; Metrology; Hall Effect;

    Abstract : 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. READ MORE

  7. 25. Topological Phase Transitions in Magnetic Nanostructures of Dirac Materials

    Author : Nezhat Pournaghavi; Carlo M. Canali; Michael Flatté; Linnéuniversitetet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Topological insulators; Magnetic materials; Quantum anomalous Hall effect; Topological magneto electric effect; Dirac semimetals; Weyl semimetals; Condensed Matter Physics; Kondenserade materians fysik;

    Abstract : 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. READ MORE