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Local spin density approximation to the density functional theory
have been highly successful for electronic structure calculations
and zero tempetarure magnetic properties of non-correlated
systems. We discuss some failure of the LSDA-scheme for the spin,
charge, and orbital effects in the bulk and surface of transition
metal systems. Starting from general formulation of LDA+U
approach with local Coulomb correlations for d- or f- ions the
different ways to go beyond the mean-field approximation which
includes in effects of the spin- and charge-fluctuations have
been analyzed. Dynamical mean field theory which takes into
account a frequency dependence of the self energy have been
combine with the first-principle scheme. The calculated
quasiparticle spectrum of magnetic transition metal systems shows
an important correlation effects. Some problems of itinerant
magnetism [1], electronic structure of transition metal oxides
[2], dimensional crossover in quasi one-dimensional systems [3]
and non-quasiparticle states in the half-metallic ferromagnets
will be discussed [4].
References [1] A. I. Lichtenstein, M. I. Katsnelson, and G. Kotliar, Phys.\ Rev.\ Lett.\ {\bf 87}, 067205 (2001). [2] A. I. Poteryaev, A. I. Lichtenstein, and G. Kotliar, Phys. Rev. Lett. {\bf 93}, 086401 (2004). [3]S. Biermann, A. Georges, A. Lichtenstein, and T. Giamarchi, Phys.\ Rev.\ Lett.\ {\bf 87}, 276405 (2001). [4] L. Chioncel, M.I. Katsnelson, R.A. de Groot, and A.I. Lichtenstein, Phys. Rev. B {\bf 68}, 144425 (2003). |