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Showing 1 to 6 of 6 for “"Kondo lattice model"”.
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Phase diagram for the S equals one-half and J equals three-halves Kondo lattice model
A Kondo lattice Hamiltonian for arbitrary total angular momentum J is formulated using a pseudofermion representation and without addition of RKKY interaction terms. An Hartree-Fock treatment is applied, and both variational and Green's function methods are used to calculate physical quantities …
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Competition and unification of Kondo coherence and magnetic ordering
… across the transition. In the quest for a toy model to envision this simultaneous collapse, we study the Kondo-Heisenberg model on the honeycomb lattice at half-filling. We study a fixed point controlling the quantum phase transition of a Kondo coherent phase to a critical phase called …
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Magnetic-field-induced antiferromagnetism in the Kondo lattice
The half-filled Kondo lattice model, augmented by a Zeeman term, serves as a useful model of a Kondo insulator in an applied magnetic field. A variational mean field analysis of this system on a square lattice, backed up by quantum Monte Carlo calculations, reveals an interesting separation of …
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Density Matrix Renormalization Group Studies of Strongly Correlated Systems in Low Dimensions
… DMRG has one drawback that it cannot handle the lattices in three dimension. However, many materials with layered structure like the high-Tc superconductors can be approximated by the two dimensional lattice, and some models can be simplified or transformed into lower dimensions without losing …
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Flussgleichungen zur Beschreibung statischer und dynamischer Eigenschaften des eindimensionalen Kondo-Gitter-Modells
In dieser Arbeit wird das eindimensionale Kondo-Gitter-Modell untersucht, das die Wechselwirkung eines Gitters lokaler magnetischer Momente mit unkorrelierten Leitungselektronen beschreibt. Mit Hilfe der Methode der kontinuierlichen unitären Transformationen (Flussgleichungen) wird das Modell im …
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Flussgleichungen für das Anderson-Gitter zur Beschreibung von Schwer-Fermion-Systemen
… charakterisiert. Als Zugang zu diesem Modell wird die von Wegner vorgeschlagene Flussgleichungsmethode verwendet, ein analytisches Verfahren, welches auf der Konstruktion eines effektiven Hamilton-Operators basiert. Ein zentrales Thema dieser Arbeit ist die Beschreibung der …