Sökning: "antiferromagnets"

Visar resultat 1 - 5 av 14 avhandlingar innehållade ordet antiferromagnets.

  1. 1. Atomistic Spin Dynamics, Theory and Applications

    Författare :Johan Hellsvik; Olle Eriksson; Lars Nordström; Ulrich Nowak; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ab initio calculations; spin dynamics; magnetization; magnetic switching; diluted magnetic semiconductors; spin glasses; ferromagnetic relaxation; ferrimagnets; antiferromagnets; Magnetism; Magnetism; Condensed matter physics; Kondenserade materiens fysik; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : The topic of this Thesis is magnetization dynamics on atomic length scales. A computational scheme, Atomistic Spin Dynamics, based on density functional theory, the adiabatic approximation and the atomic moment approximation is presented. LÄS MER

  3. 2. Anyons and antiferromagnets : two two-dimensional topics

    Författare :Torbjörn Einarsson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; antiferromagnet; two dimension; anyons; fractional statistics; Heisenberg model; torus; nonlinear sigma model; multi-component wavefuntions; spin; Néel phase; disorder; braid group;

    Sammanfattning : .... LÄS MER

  4. 3. Antiferromagnets and Luttinger Liquids: Two Strongly Correlated Systems

    Författare :Ann Mattsson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Strongly correlated systems show a variety of intriguing properties and have been extensively studied over the years. In this thesis two strongly correlated systems are discussed: the two-dimensional antiferromagnet and the Luttinger liquid. The Luttinger liquid has attracted much interest as a paradigm of non-Fermi liquid behavior. LÄS MER

  5. 4. Numerical Renormalization, Doped Antiferromagnets, and Statistics - Topics in Low Dimensional Physics

    Författare :Martin Andersson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Josephson junctions; matrix-product states; fictitious flux; phase-separation; renormalization; stripes; t-J model; anyons; DMRG;

    Sammanfattning : The first part of the thesis deals with so called numerical renormalization group methods, and in particular the density-matrix renormalization group (DMRG). This method performs extremely well for large one-dimensional quantum systems like spin-chains and Hubbard models. LÄS MER

  7. 5. Criticality and Frustration: Classical and Quantum Spin Models in Two Dimensions

    Författare :Per Fröjdh; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : We investigate two-dimensional spin models and begin with an introduction to critical phenomena with emphasis on classical systems with boundaries and conformal invariance. Then we introduce the antiferromagnetic quantum Heisenberg model with frustrating interactions. LÄS MER