Europhys. Lett., 63 (1) , pp. 125-131 (2003)
Different temperature-dependent local displacements in the underdoped and overdoped 2-x x systemN. L. Saini1, H. Oyanagi2, V. Scagnoli1, T. Ito2, K. Oka2 and A. Bianconi1
1 Unità INFM, Università di Roma "La Sapienza" P. le Aldo Moro 2, 00185 Roma, Italy
2 National Institute for Advanced Industrial Science and Technology 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
(Received 10 October 2002; accepted in final form 30 April 2003)
K-edge extended X-ray absorption fine-structure (EXAFS) measurements have been used to study the temperature-dependent local structure of the underdoped and overdoped superconducting 2-x x system. The Debye-Waller factor of the in-plane - bonds has been used as an order parameter to measure the local displacements, revealing an anomalous behavior for the underdoped case while the overdoped system shows a negligible change as a function of temperature. The results provide an evidence for a close relationship between local - displacements, electron-lattice interaction and charge inhomogeneity in the copper oxide superconductors.
74.72.Dn - La-based cuprates.
74.80.-g - Spatially inhomogeneous structures.
61.10.Ht - X-ray absorption spectroscopy: EXAFS, NEXAFS, XANES, etc.
© EDP Sciences 2003