Berlin 2012 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 45: Correlated Electrons: Poster Session
TT 45.15: Poster
Donnerstag, 29. März 2012, 15:00–19:00, Poster B
Distance dependence of the spin-spin correlation function of two Kondo impurities coupled to a one-dimensional Hubbard chain — •Alexander Tiegel, Piet Dargel, and Thomas Pruschke — Institut für Theoretische Physik, Georg-August-Universität, 37077 Göttingen, Germany
The distance dependence of the ground state spin-spin correlation function ⟨S1→·S2→⟩ of two spin-1/2 Kondo impurities antiferromagnetically attached to a one-dimensional Hubbard chain is studied at half-filling. The results are obtained via the density-matrix renormalization group (DMRG) method. In the case of weak couplings one finds a RKKY dominated behavior for all accessible distances. A crossover into the Kondo regime occurs with increasing coupling and inter-impurity distances R. It is especially studied to which extent there exists a power-law decrease of the inter-impurity correlation function. In the absence of an on-site repulsion a 1/R2 behavior of the correlations is observed for large distances and strong couplings. Furthermore the asymptotic properties of the correlation function are discussed if the Coulomb interaction is taken into account. The results are supported by perturbation theory.