Regensburg 2010 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 27: CE: Poster Session
TT 27.35: Poster
Mittwoch, 24. März 2010, 14:00–18:00, Poster D1
Temperature dependent optical conductivity of RVO3 (R=Y, Gd), LaSrFeO4 and RCoO3 (R=La, Eu) studied by ellipsometry — •Julia Küppersbusch1, Kostiantyn Shportko1, Agung Nugroho2, Thomas Palstra2, Navid Qureshi1, Marco Reuther1, Thomas Lorenz1, and Markus Grüninger1 — 1Universität zu Köln — 2Rijksuniversiteit Groningen
Spin and orbital degrees of freedom play a decisive role in strongly
correlated transition-metal oxides. Spin and orbital correlations for
instance have a strong impact on the optical transitions from the
lower to the upper Hubbard band. Our aim is a systematical study
to understand the importance of spin/orbital correlations and also
excitonic effects on the temperature dependence of the optical
spectra. We use ellipsometry from 0.75 to 5.5 eV and show results
on RVO3, LaSrFeO4, and RCoO3.
The 3d5 configuration of LaSrFeO4 does not show orbital degrees
of freedom, the spins order at 350 K, thus the behavior at lower
temperatures offers a reference for the influence of the lattice.
The T dependence of the optical data of 3d2 RVO3 can be well
described on the basis of spin/orbital correlations.
The 3d6 compounds RCoO3 allow to study the effect of a
spin-state transition on the optical data.