Berlin 2005 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 2: Correlated Electrons - Metal Insulator Transition

TT 2.3: Vortrag

Freitag, 4. März 2005, 10:45–11:00, TU H2053

Role of lattice distortion and orbital splitting in Mott-Hubbard transitions — •K. Held, A. Yamasaki, R. Arita, M. Feldbacher, and O.K. Andersen — MPI for solid state research, Stuttgart

Lattice distortions lift the degeneracy orbitals have e.g. in a cubic phase. By means of a two band model study, we show that even a small splitting of the orbitals can have a dramatic effect, if a system is close to a Mott-Hubbard transition. Then, electronic correlations grossly enhance the splitting. There can be one or two transition in which the two split bands become insulating. We also report on realistic LDA+DMFT (local density approximation + dynamical mean field theory) calculations for the pressure-induced Mott-Hubbard transition in LaMnO₃ at room temperature. Our conclusion is that the Jahn-Teller and GdFeO₃ distortion and its change are essential for the Mott-Hubbard transition.