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TT: Tiefe Temperaturen
TT 31: Correlated Electrons: Metal Insulator Transition - Part 2
TT 31.6: Talk
Thursday, March 30, 2006, 15:15–15:30, HSZ 301
Orbital fluctuations and Mott gap in LaVO3 and YVO3 — •E. Pavarini1, M. Raychaudhury2, and O.K. Andersen2 — 1IFF-Forschungzentrum Juelich, D-52425 Germany — 2MPI-FKF, Heisenbergstrasse 1, D-70569 Stuttgart
The Mott insulators LaVO3 and YVO3 have attracted a lot of attention because of their anomalous magnetic and electronic properties, which are ascribed to the interplay bewteen orbital (t2g) degrees of freedom, lattice and Coulomb repulsion. Here, by using the Nth-order Muffin Tin Orbital (NMTO)-based downfolding procedure, we construct a low energy Hubbard Hamiltonian for the partially filled t2g bands; we than solve this Hamiltonian by means of LDA+DMFT, and obtain the full self-energy matrix in orbital space; we have already applied successfully this approacht to the series of 3d1 perovskites [1]. We will show that, in the case of LaVO3 and YVO3, orbital fluctuations are strong (more for LaVO3 than for YVO3) in the high temperature paramagnetic phase, and that they play an important role also in the low temperature magnetic phases. The interplay between filling, Coulomb repulsion, crystal field splitting and band widths is discussed, and their role in determining the size of the Mott gap in LaVO3 and YVO3 clarified.
[1] E. Pavarini, S. Biermann, A. Poteryaev, A.I. Lichtenstein, A. Georges, and OK Andersen, PRL 92 176403 (2004).