Dresden 2003 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 36: Nonlinear dynamics II

DY 36.6: Vortrag

Mittwoch, 26. März 2003, 17:45–18:00, G\"OR/226

Einstein oscillator in Thallium filled Antimony skutterudites: Inelastic neutron scattering and heat capacity measurements — •Raphaël P. Hermann1, Werner Schweika2, R. Jin3, Fernande Grandjean1, David Mandrus3, Brian C. Sales3, and Gary J. Long41Department of Physics, University of Liege, Belgium — 2Institut für Festkörperforschung, Forschungszentrum Jülich — 3Solid State Division, Oak Ridge National Laboratory, U.S.A. — 4Department of Chemistry, University of Missouri-Rolla, U.S.A.

Inelastic neutron scattering measurements on several Tl filled skutterudites show a well-defined peak in the vibrational density of states. The peak energy for Tl0.5Co3.5Fe0.5Sb12, Tl0.8Co3FeSb12, and Tl0.8Co4Sb11Sn is 5.0, 4.9, and 4.7 ± 0.1 meV, respectively. This peak is absent in the unfilled CoSb3 skutterudite. Comparison of the heat capacity measurements on Tl0.8Co4Sb11Sn and CoSb3 clearly indicates a nearly localized vibrational mode associated with the No-dqrattlingNo-dq thallium atoms in this filled skutterudite compound. The inelastic neutron scattering and heat capacity measurements are both well described by a localized Einstein mode with an Einstein temperature, ΘE, of 57 ± 2 K. These experimental data provide one of the clearest examples of a local mode behavior in a concentrated metallic system. Further, the inelastic neutron scattering measurements show that substituting antimony by tin in the first near neighbor shell of the thallium atoms broadens the peak in the vibrational density of states.

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