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Magnetic Impurity in a Metal with Correlated Conduction Electrons: An Infinite Dimensions Approach

Benny Davidovich·V. Zevin
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Abstract

We consider the Hubbard model with a magnetic Anderson impurity coupled to a lattice site. In the case of infinite dimensions, one-particle correlations of the impurity electron are described by the effective Hamiltonian of the two-impurity system. One of the impurities interacts with a bath of free electrons and represents the Hubbard lattice, and the other is coupled to the first impurity by the bare hybridization interaction. A study of the effective two-impurity Hamiltonian in the frame of the 1/N expansion and for the case of a weak conduction-electron interaction (small U) reveals an enhancement of the usual exponential Kondo scale. However, an intermediate interaction (U/D = 1 - 3), treated by the variational principle, leads to the loss of the exponential scale. The Kondo temperature T_K of the effective two-impurity system is calculated as a function of the hybridization parameter and it is shown that T_K decreases with an increase of U. The non-Fermi-liquid character of the Kondo effect in the intermediate regime at the half filling is discussed.

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Benny Davidovich, V. Zevin. 1997-06-27. Magnetic Impurity in a Metal with Correlated Conduction Electrons: An Infinite Dimensions Approach. https://doi.org/10.1103/physrevb.57.7773

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