Search for dissertations about: "Emil Bergholtz"
Showing result 1 - 5 of 11 swedish dissertations containing the words Emil Bergholtz.
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1. One-dimensional theory of the quantum Hall system
Abstract : The quantum Hall (QH) system---cold electrons in two dimensions in a perpendicular magnetic field---is a striking example of a system where unexpected phenomena emerge at low energies. The low-energy physics of this system is effectively one-dimensional due to the magnetic field. READ MORE
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2. Knotted Nodal Band Structures
Abstract : It is well known that in conventional three dimensional (3D) Hermitian two band models, the intersections between the energy bands are generically given by points. The typical example are Weyl semimetals, where these singular points can be effectively described as Weyl fermions in the low energy regime. READ MORE
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3. Topology Meets Frustration : Exact Solutions for Topological Surface States on Geometrically Frustrated Lattices
Abstract : One of the main features of topological phases is the presence of robust boundary states that are protected by a topological invariant. Famous examples of such states are the chiral edge states of a Chern insulator, the helical edge states of a two-dimensional Z2 insulator, and the Fermi arcs of Weyl semimetals. READ MORE
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4. Geometry, Topology and Emergence in Moiré Systems
Abstract : 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. READ MORE
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5. Strongly Correlated Moiré Materials
Abstract : Recent advances in materials science have established Moiré materials as a new highly tunable and versatile form of quantum matter. When two dimensional atomic layers are brought into proximity, a tiny relative twist or a slight lattice mismatch produces Moiré patterns manifested in a superlattice structure with a lattice constant that is much larger than the lattice constants of the constituent layers. READ MORE