Berlin 2005 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 23: Posters Superconductivity, Solids at Low Temperature
TT 23.17: Poster
Montag, 7. März 2005, 14:00–18:00, Poster TU D
Change of quasiparticle dispersion in crossing Tc in the underdoped cuprates — •Thomas Eckl1, Werner Hanke1, Sergey V. Borisenko2, and Jörg Fink2 — 1Institut für Theoretische Physik und Astrophysik,Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany — 2Institute for Solid State Research, IFW-Dresden, P.O. Box 27 00 16, D-01171 Dresden, Germany
One of the most remarkable properties of the high-temperature superconductors is a pseudogap regime appearing in the underdoped cuprates above the superconducting transition temperature Tc. The pseudogap continously develops out of the superconducting gap. In this contribution, we demonstrate by means of a detailed comparison between theory and experiment that the characteristic change of quasiparticle dispersion in crossing Tc in the underdoped cuprates can be understood as being due to phase fluctuations of the superconducting order parameter. In particular, we show that within a phase fluctuation model the characteristic back-turning BCS bands disappear above Tc whereas the gap remains open. Furthermore, the pseudogap rather has a U-shape instead of the characteristic V-shape of a dx2−y2-wave pairing symmetry and starts closing from the nodal k→=(π/2,π/2) directions, whereas it rather fills in at the anti-nodal k→=(π,0) regions, yielding further support to the phase fluctuation scenario.