Sökning: "edge states"

Visar resultat 1 - 5 av 94 avhandlingar innehållade orden edge states.

  1. 1. Topology Meets Frustration : Exact Solutions for Topological Surface States on Geometrically Frustrated Lattices

    Författare :Flore Kiki Kunst; Emil Bergholtz; Jack Lidmar; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Topology; boundary states; surface states; edge states; Chern insulator; Weyl semimetal; Theoretical Physics; teoretisk fysik;

    Sammanfattning : 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. LÄS MER

  3. 2. 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

  4. 3. Edge states and transition to turbulence in boundary layers

    Författare :Taras Khapko; Dan Henningson; Philipp Schlatter; Yohann Duguet; Rich Kerswell; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary layer; transition to turbulence; direct numerical simulation; edge state; free-stream turbulence; bypass transition; probabilistic cellular automaton; turbulence at the onset; laminar–turbulent coexistence; laminarisation; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : The focus of this thesis is the numerical study of subcritical transition to turbulence in boundary-layer flows. For the most part, boundary layers with uniform suction are considered. Constant homogeneous suction counteracts the spatial growth of the boundary layer, rendering the flow parallel. LÄS MER

  5. 4. Reactivity of Transition-Metal Compounds from Electronic Structure

    Författare :Aleksandra Vojvodic; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; magnetic edge states; electronic structure; density-functional theory; growth; surface states and resonances; nitrides; density of states; hydrodesulphurisation; sulphides; steam reforming; transition-metal carbides; Bronsted-Evans Polanyi relation; scaling relations; adsorption; descriptor; reactivity; catalysis;

    Sammanfattning : Transition-metal carbides (TMC's), nitrides, and sulfides belong to the class of materials known as transition-metal compounds (TMX's). Besides having intriguing properties, these materials are relevant for, e.g., growth and catalysis. LÄS MER

  7. 5. Transition to turbulence in the asymptotic suction boundary layer

    Författare :Taras Khapko; Dan Henningson; Philipp Schlatter; Yohann Duguet; Marc Avila; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary layers; instability; laminar-turbulent transition; dynamical systems; edge states; near-wall turbulence; laminarisation;

    Sammanfattning : The focus of this thesis is on the numerical study of subcritical transition to turbulence in the asymptotic suction boundary layer (ASBL). Applying constant homogeneous suction prevents the spatial growth of the boundary layer, granting access to the asymptotic dynamics. LÄS MER