Berlin 2005 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 4: Symposium Superconducting Cuprates

TT 4.7: Vortrag

Freitag, 4. März 2005, 16:45–17:00, TU H104

Novel neutron resonance mode in d_x²−y² superconductors — •Ilya Eremin¹, Dirk K. Morr², Andrey V. Chubukov³, Karl Bennemann¹, and Michael R. Norman⁴ — ¹Institut für Theoretische Physik, Freie Universität Berlin, 14195 Berlin, Germany — ²Department of Physics, University of Illinois at Chicago, Chicago, IL 60607 — ³Department of Physics, University of Wisconsin, Madison, WI 53706 — ⁴Materials Science Division, Argonne National Laboratory, Argonne, IL 60439

We show that a new resonant magnetic excitation at incommensurate momenta, observed recently by inelastic neutron scattering experiments on YBa₂Cu₃O_6.85 and YBa₂Cu₃O_6.6, is a spin exciton. Its location in the magnetic Brillouin zone and its frequency are determined by the momentum dependence of the particle-hole continuum. We identify several features that distinguish this novel mode from the previous resonance mode observed near Q=(π,π), such as its intensity maximum which occurs in a different part of the magnetic Brillouin zone.