Dresden 2003 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 16: Mechanismus der HTSL
TT 16.8: Vortrag
Donnerstag, 27. März 2003, 12:10–12:25, HSZ304
Condensation Energy and Quasiparticle Dispersion in Superconductors with Phase Fluctuations — •Thomas Eckl1, Enrico Arrigoni1, Werner Hanke1, and Douglas J. Scalapino2 — 1Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany — 2Department of Physics, University of California, Santa Barbara, CA 93106-9530 USA
Recent reflectivity measurements have shown a violation of the in-plane optical integral in underdoped Bi2Sr2CaCu2O8+δ (Bi2212) up to frequencies much higher than those expected by standard BCS theory. The sum rule violation can be related to a decrease of in-plane kinetic energy upon entering the superconducting state below Tc. We show that a mechanism based upon phase fluctuations of the superconducting order parameter can account for this change of in-plane kinetic energy at Tc. Within this description, the pseudogap originates from phase fluctuations of a dx2−y2 pairing gap, whose amplitude forms at TcMF, well above the actual superconducting transition at Tc. This kinetic-energy change is accompanied by a complete change of the quasiparticle dispersion, from a BCS-like dispersion below Tc, to a completely new No-dqphase-disorderedNo-dq dipersion above Tc.