Dresden 2009 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 30: Superconductivity: Cuprate High-Temperature Superconductors 2

TT 30.1: Vortrag

Mittwoch, 25. März 2009, 14:00–14:15, HSZ 304

Enhancement of the incommensurate magnetic order by an applied magnetic field in underdoped YBa₂Cu₃O_6.45 — •Daniel Haug¹, Vladimir Hinkov¹, Anton Suchaneck¹, Dmytro Inosov¹, Niels Christensen², Christof Niedermayer², Philippe Bourges³, Yvan Sidis³, Ji Tae Park¹, Alexandre Ivanov⁴, Chengtian Lin¹, Joël Mesot², and Bernhard Keimer¹ — ¹Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany — ²Paul-Scherrer-Institut, Villigen, Switzerland — ³Laboratoire Léon Brillouin, CEA-CNRS Saclay, France — ⁴Institut Laue-Langevin, Grenoble, France

The discovery of quantum oscillations in the high-temperature superconductor YBa₂Cu₃O_6.5 above its critical magnetic field showed that the concepts of Fermi liquid theory are applicable to the strongly correlated electron system in the underdoped cuprates. However, the observation of small electron pockets in these experiments puts a new question as such pockets are incompatible with band structure calculations and the Fermi surface topology found in angle-resolved photoemission at zero magnetic field. Our recent neutron scattering experiments on YBa₂Cu₃O_6.45 reveal an enhancement of the static incommensurate magnetic signal at low temperatures when applying an external magnetic field. This field-enhanced magnetic order may lead to a Fermi surface reconstruction and thus provide a natural explanation for the unexpected Fermi surface topology observed in the quantum oscillation experiments at high magnetic fields.