Hamburg 2001 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 11: Fachsymposium: Eindimensionale Übergangsmetalle
TT 11.7: Hauptvortrag
Dienstag, 27. März 2001, 17:30–18:00, A
Dynamics of charge excitations in the NaV2O5 spin ladder system - experiment and theory. — •M. S. Golden1, S. Atzkern1, M. Knupfer1, J. Fink1, A. N. Yaresko2, V. N. Antonov2, A. Huebsch3, C. Waidacher3, K. W. Becker3, W. von der Linden4, G. Obermeier5, and S. Horn5 — 1Institut fuer Festkoerperfoschung, IFW Dresden, Postfach 270016, D-01171 Dresden, Germany — 2Max-Planck-Institut fuer Physik Komplexer Systeme, D-01187 Dresden, Germany — 3Institut fuer Theoretische Physik, TU Dresden, D-01062 Dresden, Germany — 4Institut fuer Theoretische Physik, TU Graz, A-8010 Graz, Austria — 5Institut fuer Physik, Universitaet Augsburg, D-86159 Augsburg, Germany
We present a joint experimental and theoretical investigation of the dynamics of the charge excitations in the spin ladder system NaV2O5 measured using high resolution electron energy-loss in transmission. The optical conductivities derived from the loss data were compared to LSDA+U calculations, allowing an estimation of U. Additionally, the q-dependent loss functions were simulated within an effective 16-V-site cluster model, indicating both the validity of the hopping parameters derived from a tight binding fit to the bandstructure and the presence of moderate Coulomb interactions between the electrons within the ab plane.