Berlin 2012 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 73: Focussed session: Frontiers of electronic structure theory: Strong correlations from first principles V (jointly with TT)

O 73.9: Vortrag

Donnerstag, 29. März 2012, 18:15–18:30, HE 101

Charge Kondo effect in PbTe doped with Tl impurities — •Theo Costi¹ and Veljko Zlatic² — ¹Peter Grünberg Institut (PGI-2) and Institut for Advanced Simulation (IAS-3), Forschungszentrum Jülich, 52425 Jülich, Germany — ²Institute of Physics, 10001 Zagreb, Croatia

Semiconducting PbTe is one of the most interesting materials for thermoelectric applications. When doped with a small concentration of Tl impurities, acting as acceptors, a number of anomalous properties are found: e.g.,beyond a critical concentration of about 0.3% Tl, the system exhibits superconductivity with remarkably high critical temperatures for such a low carrier system. This and other anomalous phenomena prompted the idea that Tl impurities act as negative U centres leading to a charge Kondo effect and to superconductivity. Here, we combine ab-initio information and numerical renormalization group methods to explore the consequences of this model for the normal state properties, showing that it can explain a number of features in the temperature and doping dependence of the resistivity, and carrier density. Predictions for the photoemission spectrum are also discussed [1].
[1] T. A. Costi and V. Zlatić, Phys. Rev. Lett. (arXiv:1109.1824).