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Doping-dependent charge order correlations in electron-doped cuprates

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Science Advances  12 Aug 2016:
Vol. 2, no. 8, e1600782
DOI: 10.1126/sciadv.1600782
  • Fig. 1 CO in LCCO.

    (A) Scattering geometry along the Cu–O bond direction (see text for details). (B) RXS θ scans for LCCO (x = 0.08, Tc ~ 20 K) at various temperatures. au, arbitrary units. (C) CO peaks at different temperatures obtained upon subtracting the 340 K data from those at lower temperatures. (D) Data (60, 140, and 220 K) from (C) with their maxima normalized to unit. The curves were offset for clarity, and the width of gray bars represents the half width at half maximum of the 60 K data.

  • Fig. 2 Temperature and doping dependence of CO in NCCO.

    (A to F) Temperature dependence of θ scans for six doping levels of NCCO. Yellow diamonds in (A) to (F) show the H location of the low-temperature peak maxima (29). (G) Temperature dependence of the CO peak maximum after subtraction of the 340 K peak maximum (29), extracted from the data in (D) to (F). The vertical scales in (A) to (F) are proportional to the detector reading normalized to the incoming photon flux (29). Note that the intensity difference in the vertical scale of (G) is plotted in the same units as in (D) to (F). The error bars in (G) represent the systematic errors associated with the experiment (29).

  • Fig. 3 Phase diagram of CO in NCCO.

    (A) Doping dependence of QCO(x) compared with the separation between the segments of the Fermi surface near (π,0), as determined from ARPES (white bar in the inset). The inset shows a representative ARPES Fermi surface NCCO for x = 0.15 (left) and a schematic of the AFM-folded Fermi surface (right), with electron (blue) and hole (red) pockets. (B) Phase diagram of NCCO adapted from the study by Motoyama et al. (33), including the AFM and superconductivity (SC) region, the pseudogap temperature (T), and the instantaneous antiferromagnetic correlation length (ξ) (normalized to the tetragonal lattice constant a) determined via INS. Superimposed red and blue circles represent TOCO and TSCO, respectively. Thick semitransparent blue and red lines are guides to the eye. In (A) and (B), the horizontal error bars represent the uncertainty in the experimental determination of doping level (29). The vertical error bars in (B) indicate the uncertainty in locating the temperature where TOCO and TSCO deviate from their respective high-temperature behaviors (29).

  • Fig. 4 CO versus superconductivity.

    (A and B) Measurements of an x = 0.14 sample (Tc ~ 22 K) (A) at 0 T as a function of temperature above and below Tc, and (B) at 10 K for 0.2 and 6.0 T. The halos around the curves in (B) represent the experimental uncertainty from magnetic field–induced mechanical distortions of the sample environment (29). Data in (A) and (B) were obtained using different instruments at the same beamline (29).

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/2/8/e1600782/DC1

    Supplementary Materials and Methods

    table S1. Summary of NCCO samples used for RXS measurements.

    fig. S1. ARPES measured Fermi surface of NCCO for x = 0.15.

    fig. S2. Comparison between CO wave vector measured by RXS and inferred by ARPES.

    fig. S3. Patching of the data acquired in the high-field diffractometer chamber at BESSY II.

    fig. S4. Schematic drawing of the scattering geometry in the high-field diffractometer chamber at BESSY II.

    fig. S5. Energy dependence of RXS scans in LCCO.

  • Supplementary Materials

    This PDF file includes:

    • Supplementary Materials and Methods
    • table S1. Summary of NCCO samples used for RXS measurements.
    • fig. S1. ARPES measured Fermi surface of NCCO for x= 0.15.
    • fig. S2. Comparison between CO wave vector measured by RXS and inferred by ARPES.
    • fig. S3. Patching of the data acquired in the high-field diffractometer chamber at BESSY II.
    • fig. S4. Schematic drawing of the scattering geometry in the high-field diffractometer chamber at BESSY II.
    • fig. S5. Energy dependence of RXS scans in LCCO.

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