NMR-STUDY OF LOCAL-STRUCTURE IN METALLIC LA2CUO4+ DELTA

We employ La-139 NMR spectroscopy as a structural probe of metallic La 2CuO4+delta. We find a distribution of lateral displacements of the ox ygen atoms which form the apices of the oxygen octahedra. We directly observe a wide distribution of structures of the La-O layer; this dist ribution is strongly temperature dependent. We present copper NQR spec tra which reveal a second, unexplained, copper site in the CuO2 planes . We show that these features are not manifestations of disturbances o f the lattice by interstitial dopants, but are the intrinsic response of La2CuO4+delta to doped holes.