Temperature dependent local Cu-O displacements from underdoped to overdoped La-Sr-Cu-O superconductor

We have studied doping evolution of the temperature dependent local Cu-O displacements in the La<Subscript>2-x </Subscript>Sr<Subscript> x </Subscript>CuO<Subscript>4</Subscript> superconductor by polarized Cu K-edge extended X-ray absorption fine structure (EXAFS) measurements. While temperature dependent Debye-Waller factor of the Cu-O bonds, measuring the local Cu-O displacements, shows an anomalous increase at low temperature for the underdoped single crystals, we do not find such a dependence for the case of the overdoped system. The results, which are discussed in the light of recent angle resolved photoemission measurements, provide an evidence for some important correlation between the doping dependent electron-lattice interaction, the charge inhomogeneities and the local Cu-O displacements in the copper oxide superconductors. Copyright Springer-Verlag Berlin/Heidelberg 2003