|
|
| VOLUME 91 | ISSUE 6 |
PAGE 339
|
| Analytical approximation for single-impurity Anderson model |
I. S. Krivenko, A. N. Rubtsov, M. I. Katsnelson+, A. I. Lichtenstein*
Department of Physics, Moscow State University, 119992 Moscow, Russia
+Radboud University, 6525AJ, Nijmegen, The Netherlands
*Institut für Theoretische Physik, Universität Hamburg, D-20355 Hamburg, Germany
|
Abstract
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 weak- and in the the strong-coupling case and
interpolates well in between. Formulae for the first-order dual
diagram correction are obtained analytically in the real-time
domain. A generalization of this scheme to a multi-orbital case can
be important for the realistic description of correlated solids.
|
|
|
Download PS file (GZipped, 180.9K)
|
Download PDF file (237K)
|
|
Список работ, цитирующих данную статью, см. здесь.
List of articles citing this article can be found here.
|
|
Home