Dresden 2011 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 35: CE: Low-dimensional Systems - Materials 3
TT 35.1: Talk
Wednesday, March 16, 2011, 14:00–14:15, HSZ 301
EELS and RIXS measurements of La1−xSr1+xMnO4, signatures of polarons — •Roberto Kraus1, Matthias Schrade1, Valentina Bisogni1, Pieter Glatzel2, Martin Knupfer1, Bernd Büchner1, and Jochen Geck1 — 1IFW Dresden, Germany — 2ESRF Grenoble, France
The manganites show a variety of magnetic and electronic phases which are connected to charge, spin and orbital degrees of freedom. One example is the single layered perovskite La1−xSr1+xMnO4. Upon hole doping new in-gap states appear and up to now it is unclear if they are of charge-transfer or Mott-Hubbard type. To characterize the excitations in the system, we have performed electron energy-loss spectroscopy (EELS) and resonant inelastic X-ray scattering (RIXS) at the Mn K-edge. The observed in-gap excitation shows a small positive dispersion, which is a sign of a delocalized excitation. As a function of temperature a clear positive shift for this peak was found in the half-doped sample, implying a strong coupling of charge and spin dynamics. We present a model of electronic polarons for the new in-gap states which are created around the doped holes. The finite dispersion provides further the indication of polaron-ploaron interactions.