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TT: Tiefe Temperaturen

TT 4: Correlated Electrons: Quantum Impurities, Kondo Physics

TT 4.6: Vortrag

Montag, 27. März 2006, 12:30–12:45, HSZ 301

Local moments formation in a t–J chain with an integrable impurity — •Guillaume Palacios and Holger Frahm — Institut für Theoretische Physik, Universität Hannover, D-30167 Hannover, Germany

We consider an integrable model describing an Anderson-like impurity coupled to an open t–J chain. Both the hybridization (coupling between the bulk chain and the impurity) and the local spectrum can be controlled without breaking the integrability of the model.

In the strong hybridization limit, we show the appearance of boundary bound states in the energy spectrum which, as a function of the parameters, permits us to distinguish four phases, from zero to three bound states. We then compute the contribution of these bound states to the response of the system to a) a uniform magnetic field and b) a local field at the impurity site. The results obtained by means of Bethe Ansatz techniques and finite size analysis allow to make contact with the physics of local moments and the Kondo effect. Results for the impurity compressibility are also presented.