Regensburg 2000 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 19: Metall-Isolatorüberg
änge

TT 19.2: Vortrag

Donnerstag, 30. März 2000, 10:00–10:15, H18

Orbital degeneracy and Mott transition in the alkali-doped Fullerenes — •Erik Koch and Olle Gunnarsson — Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart

In the alkali-doped Fullerenes the Coulomb interaction U between two electrons on the same molecule is larger than the relevant one-particle band-width. It is therefore surprising that these systems are not all Mott insulators. We show that the orbital degeneracy plays a crucial role in putting the Fullerenes in the vicinity of a Mott transition, with some being metallic, while others are insulators. Using generalized Hubbard models with realistic parameters for the Fullerenes, we discuss the effect of (integer) doping and lattice structure on the Mott transition.

[1] E. Koch, O. Gunnarsson, and R.M. Martin, cond-mat/9905351