Berlin 2012 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 43: Correlated Electrons: Metal-Insulator Transition 2

TT 43.6: Vortrag

Donnerstag, 29. März 2012, 16:30–16:45, H 3010

Orbital-order melting in rare-earth manganites — •Andreas Flesch¹, Guoren Zhang¹, Erik Koch², and Eva Pavarini¹ — ¹Institute for Advanced Simulation and JARA, Forschungszentrum Jülich, 52425 Jülich, Germany — ²German Research School for Simulation Sciences, 52425 Jülich, Germany

The mechanism of orbital ordering in rare-earth manganites, in particular in LaMnO₃, has been debated since long. For LaMnO₃, it was recently shown that the purely electronic super-exchange mechanism alone cannot explain the persistence of Jahn-Teller distortions in nanoclusters at high temperature [1]. However, its role in the orbital order-to-disorder transition (orbital-order melting) remains unclear. In this talk, we present order parameter (orbital polarization) and total energy calculations based on the LDA+DMFT approach for the series of rare-earth manganites. By comparing our results to experiments, we show that super-exchange plays a minor role in the orbital-order melting transition observed in rare-earth manganites [2].

[1] E. Pavarini and E. Koch, PRL 104, 086402 (2010)

[2] A. Flesch, G. Zhang, E. Koch, and E. Pavarini, arXiv:1106.2439