X-ray absorption study of the CuO2 plane in Nd2−xCexCuO4−δ

Abstract The local structure of the CuO 2 planes in Nd 2− x Ce x CuO 4− δ ( x =0, 0.15; δ ∼0.01) has been examined by temperature-dependent Cu K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy. Three different Cu–O distances can be extracted up to at least 100 K, indicating that the atomic structure of the CuO 2 planes deviates from the T ′ structure much more than it was expected. Positions of the displaced O1 atoms for x =0.15 were obtained from comparative analysis of the experimental and calculated polarized Cu K-edge X-ray absorption near-edge structure, taking into account many-body excitations in the CuO 2 planes.