Magnetic impurity coupled to interacting conduction electrons
摘要
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 an 1/N_f expansion. The correlations among the conduction electrons are described by a Hubbard Hamiltonian and are treated to lowest order in the interaction strength. We find that their effect on the Kondo temperature, T_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 T_K. Secondly, the bare Kondo exchange coupling is enhanced as spin fluctuations are enlarged. In total, T_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.
引用
@article{arxiv.cond-mat/9510062,
title = {Magnetic impurity coupled to interacting conduction electrons},
author = {Tom Schork},
journal= {arXiv preprint arXiv:cond-mat/9510062},
year = {2009}
}
备注
ReVTeX 19 pages, 3 uuenconded postscript figures