Dresden 2003 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 21: Phasendiagramm der HTSL
TT 21.4: Hauptvortrag
Freitag, 28. März 2003, 11:35–12:05, HSZ304
Electron doped high-temperature superconductors: The dark side of the phase diagram — •Lambert Alff — Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Walther-Meißner-Str. 8, 85748 Garching.
The fascinating phenomenon of high-temperature superconductivity arises upon doping an antiferromagnetic Mott-insulator with charge carriers. The vast majority of theoretical and experimental work has focused on hole doping, while the electron doped side of the phase diagram has been neglected. The study of electron doped high-temperature superconductors (HTS), however, may contribute to enhance our understanding of the whole cuprate phase diagram. This talk will concentrate on two important questions: (i) while it is widely accepted that the symmetry of the order parameter in hole doped HTS is dx2−y2-wave like, the symmetry has not yet been unambiguously determined for electron doped HTS; (ii) the existence and the doping dependence of a pseudogap in the excitation spectra of the electron doped HTS is still under question. Recent results indicate that around optimum doping the characteristic pseudogap temperature is - in contrast to hole doped HTS - smaller than the critical temperature, indicating a possible coexistence of two competing order parameters.