Berlin 2005 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 23: Posters Superconductivity, Solids at Low Temperature
TT 23.29: Poster
Montag, 7. März 2005, 14:00–18:00, Poster TU D
Lattice dynamics and electron-phonon coupling in YBa2Cu4O8 — •V. Pankoke1, R. Heid2 und K.-P. Bohnen2 — 1Forschungszentrum Karlsruhe, Institut für Wissenschaftliches Rechnen, P.O.B. 3640, D-76021 Karlsruhe — 2Forschungszentrum Karlsruhe, Institut für Festkörperphysik, P.O.B. 3640, D-76021 Karlsruhe
The superconducting properties of YBaCuO depend strongly on the oxygen content thus it is of crucial importance to understand the lattice dynamics and the electron-phonon coupling as function of doping. While it has been possible to investigate these quantities recently with modern ab-initio methods [1] studying doping effects is a much more difficult task due to the loss of translational invariance. Fortunately, some ordered structures exist which can be treated rigorously with moddern density functional methods. Among these YBa2Cu4O8 plays a special role due to the fact that this compound contains double Cu-O chains a structural building block which is very rare in the high-Tc ccompounds. Using the density functional perturbation approach we have studied the lattice dynamics and electron-phonon coupling of YBa2Cu4O8. Results will be compared with available experimental data. Good agreement between calculated and measured vibration frequencies was obtained however eigenvectors inferred from experiments differ in some cases substantially from the calculated ones. These differences will also be discussed.
[1] K.-P. Bohnen, R. Heid, M. Krauss, Europhys. Lett. 64, 104 (2003)