Dresden 2006 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 30: Superconductivity: Twenty Years High-T_c Cuprates - Recent Progress

TT 30.7: Vortrag

Donnerstag, 30. März 2006, 15:30–15:45, HSZ 02

Resonant spin excitations in the id-density wave state: probe for the pseudogap scenario in underdoped cuprates — •Jan-Peter Ismer¹, Ilya Eremin^1,2, and Dirk K. Morr³ — ¹Max-Planck Institut für Physik komplexer Systeme, D-01187 Dresden, Germany — ²Institut für Mathematische und Theoretische Physik, Technische Universität Carolo-Wilhelmina zu Braunschweig, D-38106 Braunschweig, Germany — ³Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA

Inelastic neutron scattering (INS) experiments probing dynamical spin susceptibility in the pseudogap phase of the high-T_c cuprates are addressed in the framework of the ordered d-density wave(DDW) state. In particular, we analyze the formation of the resonance peak at the antiferromagnetic wave vector Q_AF=(π,π) and its dispersion in three different ordered states: d-wave superconductor (DSC), DDW state, and coexisting DDW and DSC states. In particular, we find that the resonance excitations in the DDW-state exists in a narrow region around (π,π) forming nearly no dispersion due to peculiar structure of the Fermi surface. At the same time, in the combined DDW+DSC-state the resonance peak dispersion is determined mainly by the superconducting gap, although both phases interfere around (π,π) yielding a non-monotonic intensity cusp of the resonance peak dispersion. A comparison with existing INS experiments shows certain constraints on the application of the DDW-scenario for the pseudogap in underdoped cuprates.