Regensburg 2007 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 11: Quantum Impurities, Kondo Physics

TT 11.1: Vortrag

Dienstag, 27. März 2007, 09:30–09:45, H19

Simultaneous ferromagnetic and semiconductor-metal transition in EuO — Michael Arnold and •Johann Kroha — Physikalisches Institut, Nussallee 12, 53115 Bonn

We develop a theory for the simultaneous para-to-ferromagnetic and semiconductor to metal transition in O-depleted EuO. An analysis of the total charge conservation across the transition indicates that strong Coulomb correlations in the localized O-defect states must play a crucial role. This leads to a generalized Anderson impurity model with Stoner-like magnetic correlations in the conduction band and a dilute concentration of Anderson impurities in the semiconducting gap. We solve this model using a self-consistent Non-Crossing Approximation.