Sökning: "quantum Hall effect"

Visar resultat 16 - 20 av 37 avhandlingar innehållade orden quantum Hall effect.

1. 16. Magnetotransport characterization of epitaxial graphene on SiC

   Författare :Samuel Lara Avila; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; quantum metrology; weak localization; magnetotransport; quantum Hall effect; many-electron systems; epitaxial graphene;

   Sammanfattning : Low-temperature magnetotransport is used to characterize graphene grown epitaxially on the silicon face of 4H silicon carbide (SiC/G). Observation of half-integer quantum Hall effect (QHE) in large Hall bars, patterned across several terraces of the SiC substrate, suggest that monolayer graphene grows continuously over defects. LÄS MER

3. 17. Quantum Hall Skyrmions and Edge Spin Textures

   Författare :Kennet Lejnell; Carlos Tejedor; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Theoretical Physics; teoretisk fysik;

   Sammanfattning : In the quantum Hall effect, new and surprising phenomena continue to be uncovered. For example, in quantum Hall ferromagnets Skyrmions have been observed---these quasiparticles carry electric charge and a large spin. The spin is ordered in a beautiful wavelike pattern, as shown on the front of this thesis. LÄS MER

4. 18. Interaction between electronic and vibrational edge states in graphene

   Författare :Anton Vikström; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; collective excitations; quantum acous- tics; quantum Hall effect; edge waves; graphene; solitons;

   Sammanfattning : A sheet of graphene in a magnetic field perpendicular to the sheet has electronic edge states with nonzero velocities. These edge states are localized to the edge of the sheet on the order of the magnetic length. LÄS MER

5. 19. Quantum Transport Theory in Graphene

   Författare :Anders Bergvall; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; quantum coherent electron transport; nanoribbons; FT-LDOS; grain boundaries; tight-binding; graphene;

   Sammanfattning : In this thesis, we focus on different aspects of electron transport in nanostructured graphene (such as graphene nanoribbons). Wedevelop and implement numerical methods to study quantum coherent electron transport on an atomistic level, complemented by analytical calculations based on the Dirac approximation valid close to the points $\vec{K}$ and $\vec{K}^\prime$ in the graphene Brillouin zone. LÄS MER

7. 20. Geometry, Topology and Emergence in Moiré Systems

   Författare :Ahmed Abouelkomsan; Emil Johansson Bergholtz; Felix von Oppen; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Moiré materials; Topological phases; Fractional Chern insulators; Quantum geometry; Quantum Hall effects; Theoretical Physics; teoretisk fysik;

   Sammanfattning : The experimental discovery of correlated insulators and superconductivity in highly tunable Van der Waals heterostructures, such as twisted bilayer graphene, has highlighted the role of moiré patterns, resulting from tiny relative twists or lattice constant mismatches, in realizing strongly correlated physics. A key ingredient is the existence of very narrow flat bands where interaction effects are dominant. LÄS MER