Dresden 2003 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 16: Mechanismus der HTSL

TT 16.1: Hauptvortrag

Donnerstag, 27. März 2003, 09:30–10:00, HSZ304

Collective Spin Excitations and their Role in High Temperature Superconductivity — •Bernhard Keimer¹, Clemens Ulrich¹, Vladimir Hinkov¹, Bing Liang¹, Chengtian Lin¹, Philippe Bourges², Stephane Pailhes², Louis-Pierre Regnault², and Yvan Sidis³ — ¹Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany — ²Laboratoire Leon Brillouin, CEA-CNRS, Saclay, France — ³CEA Grenoble, France

An unusual collective spin excitation mode has been observed by inelastic neutron scattering in the high temperature superconductors YBa2Cu3O7 [1], Bi2Sr2CaCu2O8 [2] and Tl2Ba2CuO6 [3] below their superconducting transition temperatures. Manifestations of a strong interaction of this mode with charged quasiparticles are apparent in photoemission and tunneling spectra, among others. This has stimulated numerous theories that ascribe a key role to spin excitations in the mechanism of high temperature superconductivity. In this talk we summarize the present situation and present some of the latest neutron data showing that some high temperature superconductors support multiple magnetic collective modes.

[1] P. Bourges et al., Science 288, 1234 (2000); H.F. Fong et al., Phys. Rev. B 61, 14773 (2000). [2] H.F. Fong et al., Nature 398, 588 (1999); H. He et al., Phys. Rev. Lett. 86, 1610 (2001). [3] H. He et al., Science 295, 1045 (2002).