Two-dimensional geometry of spin excitations in the high-transition-temperature superconductor YBa2Cu3O6+x

V Hinkov; S Pailhès; P Bourges; Y Sidis; A Ivanov; A Kulakov; C T Lin; D P Chen; C Bernhard; B Keimer

doi:10.1038/nature02774

Two-dimensional geometry of spin excitations in the high-transition-temperature superconductor YBa2Cu3O6+x

Nature. 2004 Aug 5;430(7000):650-4. doi: 10.1038/nature02774.

Authors

V Hinkov¹, S Pailhès, P Bourges, Y Sidis, A Ivanov, A Kulakov, C T Lin, D P Chen, C Bernhard, B Keimer

Affiliation

¹ Max-Planck-Institut für Festkörperforschung, 70569 Stuttgart, Germany.

PMID: 15295593
DOI: 10.1038/nature02774

Abstract

The fundamental building block of the copper oxide superconductors is a Cu4O4 square plaquette. The plaquettes in most of these materials are slightly distorted to form a rectangular lattice, for which an influential theory predicts that high-transition-temperature (high-T(c)) superconductivity is nucleated in 'stripes' aligned along one of the axes. This theory received strong support from experiments that indicated a one-dimensional character for the magnetic excitations in the high-T(c) material YBa2Cu3O6.6 (ref. 4). Here we report neutron scattering data on 'untwinned' YBa2Cu3O6+x crystals, in which the orientation of the rectangular lattice is maintained throughout the entire volume. Contrary to the earlier claim, we demonstrate that the geometry of the magnetic fluctuations is two-dimensional. Rigid stripe arrays therefore appear to be ruled out over a wide range of doping levels in YBa2Cu3O6+x, but the data may be consistent with liquid-crystalline stripe order. The debate about stripes has therefore been reopened.