Magnetic impurity coupled to interacting conduction electrons
- Max-Planck-Institut fuer Physik komplexer Systeme, Bayreuther Strasse 40 Haus 16, D-01187 Dresden (Germany)
We consider a magnetic impurity which interacts by hybridization with a system of weakly correlated electrons and determine the energy of the ground state by means of a 1/{ital N}{sub {ital f}} expansion. The correlations among the conduction electrons are described by a Hubbard Hamiltonian and are treated to the lowest order in the interaction strength. We find that their effect on the Kondo temperature, {ital T}{sub {ital K}}, in the Kondo limit is twofold: first, the position of the impurity level is shifted due to the reduction of charge fluctuations, which reduces {ital T}{sub {ital K}}. Secondly, the bare Kondo exchange coupling is enhanced as spin fluctuations are enlarged. In total, {ital T}{sub {ital K}} increases. Both corrections require intermediate states beyond the standard Varma-Yafet ansatz. This shows that the Hubbard interaction does not just provide quasiparticles, which hybridize with the impurity, but also renormalizes the Kondo coupling. {copyright} {ital 1996 The American Physical Society.}
- OSTI ID:
- 279089
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 53, Issue 9; Other Information: PBD: Mar 1996
- Country of Publication:
- United States
- Language:
- English
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