Dresden 2003 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 14: Postersitzung III (Neue u. unkonventionelle Supraleiter, Anwendungen der Supraleitung, Dünne Schichten, JJs und SQUIDs, Schwere Fermionen, Kondo-Systeme)
TT 14.31: Poster
Mittwoch, 26. März 2003, 14:30–19:00, P2c
Orbital state and magnetic properties of LiV2O4 — •Georg Keller1, Igor Nekrasov2, Zlata V. Pchelkina2, Thomas Pruschke1, Karsten Held3, Alexander Krimmel1, Dieter Vollhardt1, and Vladimir I. Anisimov2 — 1Theoretische Physik III, Institut für Physik, Universität Augsburg, 86135 Augsburg — 2Institut für Metallphysik, Ekaterinburg GSP-170, Russland — 3Max Planck Institut für Festkörperforschung, 70569 Stuttgart
LiV2O4 is one of the most puzzling compounds among transition metal oxides because of its heavy fermion like behavior at low temperatures. In this paper we present results for the orbital state and magnetic properties of LiV2O4 obtained from a combination of density functional theory within the local density approximation and dynamical mean-field theory (DMFT). The DMFT equations are solved by quantum Monte Carlo simulations. The trigonal crystal field splits the V 3d orbitals such that the a1g and egπ orbitals cross the Fermi level, with the former being slightly lower in energy and narrower in bandwidth. In this situation, the d-d Coulomb interaction leads to an almost localization of one electron per V ion in the a1g orbital, while the egπ orbitals form relatively broad bands with 1/8 filling. The theoretical high-temperature paramagnetic susceptibility χ(T) follows a Curie-Weiss law with an effective paramagnetic moment peff=1.65 in agreement with the experimental results.