Abstract
Diffuse x-ray scattering measurements reveal that the optimally doped superconductor is intrinsically modulated due to the formation of a kinetically limited 4-unit-cell superlattice, , along the shorter Cu-Cu bonds. The superlattice consists of large anisotropic displacements of Cu, Ba, and O atoms, respectively, which are correlated over unit cells in the plane, and appears to be consistent with the presence of an O-ordered “ortho-IV” phase. Long-range strains emanating from these modulated regions generate an inhomogeneous lattice which may play a fundamentally important role in the electronic properties of yttrium-barium-copper-oxides.
- Received 23 December 2003
DOI:https://doi.org/10.1103/PhysRevLett.93.157008
©2004 American Physical Society