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TT: Tiefe Temperaturen
TT 5: Superconductivity - Mechanisms, Phase Diagram, Competing Order
TT 5.1: Vortrag
Freitag, 4. März 2005, 18:00–18:15, TU H104
Interplay between competing and coexisting ground states in electron doped cuprates — •Yoshiharu Krockenberger1,2, Andreas Winkler3, Bettina Welter3, Dirk Manske2, Michio Naito4, and Lambert Alff5 — 1NTT Basic Research Laboratories, NTT Corporation, 3-1 Wakamiya, Morinosato, Atsugi-shi, Kanagawa 243-0198, Japan — 2Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany — 3Walther-Meissner-Institute, Bayerische Akademie der Wissenschaften, 85748 Garching, Germany — 4Department of Applied Physics, Tokyo University of Agriculture and Technology (TUAT), 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan — 5Vienna University of Technology, ISAS, Applied Electronic Materials, Gusshausstr. 27-29/366, A-1040 Wien, Austria
The ground state of superconductors is characterized by the long-range order of condensed Cooper pairs: this is the only order present in conventional superconductors. The high-Tc superconductors, in contrast, exhibit more complex phase behaviour, which might indicate the presence of other competing ground states. Here we report the existence of a second order parameter hidden within the superconducting phase of the underdoped (electron-doped) high-Tc superconductor Pr2−xCexCuO4+y. The existence of a pseudogap when superconductivity is suppressed excludes precursor superconductivity as its origin. This supports the picture that the physics of high-Tc is determined by the interplay between competing and coexisting ground states.