Correction for Zhou et al., Anomalous expansion of the copper-apical-oxygen distance in superconducting cuprate bilayers

PHYSICS Correction for “Anomalous expansion of the copper-apical-oxygen distance in superconducting cuprate bilayers,” by Hua Zhou, Yizhak Yacoby, Vladimir Y. Butko, Gennady Logvenov, Ivan Božović, and Ron Pindak, which appeared in issue 18, May 4, 2010, of Proc Natl Acad Sci USA (107:8103–8107; first published April 19, 2010; 10.1073/pnas.0914702107).

The authors note that due to a printer's error, the figure legends for Figs. 5, 6, and 7 do not correspond to the proper figure. The figures and their corrected legends appear below.

Fig. 5.

2D electron density (ED) profiles along (100) and (110) atomic planes of the M-I bilayer system. The EDs were determined from the experimentally measured diffraction intensities using the COBRA technique. Cold colors represent low ED while warmer colors represent higher ED. Schematic cross-sections of the complete tetragonal unit cell along each atomic plane are illustrated near the sides of the two respective panels. (Left) In (100) plane, the white lines highlight the projected shapes of the CuO₆ octahedra, in particular the elongation near the surface. (Right) In (110) plane, the white lines highlight the projected profiles of the La-apical O planes, in particular the corrugation near the surface.

Fig. 6.

Variation of the interatomic distances in single-phase metallic films. (A) The measured Cu(Al) − apical O distance, c_A, varies as a function of the nominal position of Cu(Al) atoms inside the refined structure. The data from four single-phase metallic films and the average over the four are presented. The lower and upper arrows represent the bulk values of c_A for the LSAO substrate and for La₂CuO₄ insulator (I), respectively. (B) The comparison of c_A, c₁, and c₂, averaged for each unit cell, as a function of Z position from metallic single-phase samples. (Inset) the lattice constant c₀ as a function of Z. The dotted line represents the bulk substrate value. The horizontal dashed line is the average value of c₀ in bilayers extracted from the electron density, as described in the text. In A, B and the Inset, the vertical dashed lines represent the nominal substrate/metal interface.

Fig. 7.

The comparison of the averaged c_A over measured single-phase metallic (M) and superconducting (S) films and M+I bilayers. The lower and upper arrows represent the bulk values of c_A for the substrate and for the insulator, respectively. The vertical dashed lines and the dotted line represent the nominal substrate/metal interface and metal/insulator interface, respectively.