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TT: Fachverband Tiefe Temperaturen

TT 19: Correlated Electrons: (General) Theory 2

TT 19.3: Vortrag

Dienstag, 27. März 2012, 10:00–10:15, H 3010

What do LaCoO₃ and ⁴He- ³He mixtures have in common? — •Jan Kuneš and Vlastimil Křápek — Institute of Physics, AS CR, Cukrovarnicka 10, Praha 6, Czech Republic

The perovskite LaCoO₃ has been studied for almost half a century for its peculiar magnetic and transport properties. It is generally accepted that quasi-degeneracy of a magnetic and non-magnetic multiplets is the key feature of this material, however, the understanding how it affects its physics is far from complete. We have used a two-band Hubbard model as a minimum description of a material with competing atomic states. Using the dynamical mean-field theory we have studied the temperature dependencies of the magnetic susceptibility and the one-particle spectra. At intermediate temperatures we have observed formation of a two-sublattice order, which can be understood by mapping the Hubbard model on the classical Blume-Emery-Griffiths model.