Berlin 2005 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 4: Symposium Superconducting Cuprates

TT 4.9: Vortrag

Freitag, 4. März 2005, 17:15–17:30, TU H104

Lattice dynamics and electron-phonon coupling in YBa₂Cu₃O_6.5 — •K.-P. Bohnen¹, V. Pankoke² und R. Heid¹ — ¹Forschungszentrum Karlsruhe, Institut für Festkörperphysik, P.O.B. 3640, D-76021 Karlsruhe — ²Forschungszentrum Karlsruhe, Institut für Wissenschaftliches Rechnen, P.O.B. 3640, D-76021 Karlsruhe

Recently the lattice dynamics of YBa₂Cu₃O₇ has been calculated successfully with modern ab-initio density functional methods [1]. However, the superconducting properties depend sensitively on the oxygen content thus it is of great interest to study the lattice dynamics and the electron-phonon coupling as function of doping. Here we present results for the Ortho-II phase of YBa₂Cu₃O_6.5 which has been possible to treat in detail with density-functional perturbation approach. The structure, lattice dynamics and electron-phonon coupling has been determined and will be compared with available experimental data as well as with results for YBa₂Cu₃O₇. The calculations indicate that the oxygen-apex modes are most strongly affected by doping.

[1] K.-P. Bohnen, R. Heid, M. Krauss, Europhys. Lett. 64, 104 (2003)