Analytical approximation for single-impurity Anderson model

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Erscheinungsjahr:
2010
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  • We propose a new renormalized strong-coupling expansion to describe the electron spectral properties of single-band Anderson impurity problem in a wide energy range. The first-order result of our scheme reproduces well the entire single-electron spectrum of correlated impurity with the Kondo-like logarithmic contributions to the self energy and the renormalization of atomic resonances due to hybridization with conduction electrons. The Friedel sum rule for a half-filled system is fulfilled. The approach is based on so-called dual transformation, so that the series is constructed in vertices of the corresponding atomic Hamiltonian problem. The atomic problem of single impurity has a degenerate ground state, so the application of the perturbation theory is not straightforwardatomic resonances. Proposed expansion contains a small parameter in the weakand in the strong-coupling case and interpolates well in between. Formulae for the first-order dual diagram correction are obtained analytically in the realtime domain. A generalization of this scheme to a multi-orbital case can be important for the realistic description of correlated solids. © 2010 Pleiades Publishing, Ltd.
  • We propose a new renormalized strong-coupling expansion to describe the electron spectral properties of single-band Anderson impurity problem in a wide energy range. The first-order result of our scheme reproduces well the entire single-electron spectrum of correlated impurity with the Kondo-like logarithmic contributions to the self energy and the renormalization of atomic resonances due to hybridization with conduction electrons. The Friedel sum rule for a half-filled system is fulfilled. The approach is based on so-called dual transformation, so that the series is constructed in vertices of the corresponding atomic Hamiltonian problem. The atomic problem of single impurity has a degenerate ground state, so the application of the perturbation theory is not straightforward. We construct a special approach dealing with symmetry-broken ground state of the atomic problem. The renormalization ensures a convergence near the frequencies of atomic resonances. Proposed expansion contains a small parameter in the weakand in the strong-coupling case and interpolates well in between. Formulae for the first-order dual diagram correction are obtained analytically in the realtime domain. A generalization of this scheme to a multi-orbital case can be important for the realistic description of correlated solids.
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  • info:eu-repo/semantics/closedAccess
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Forschungsinformationssystem der UHH

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oai:www.edit.fis.uni-hamburg.de:publications/6c488e75-a3ff-4d82-8ae1-01dc70a218c7