Figure 2: CDW in Hg1201 (Tc=71 K) observed with RXD and RIXS.
From: Charge order and its connection with Fermi-liquid charge transport in a pristine high-Tc cuprate
(a) RXD spectra collected near the CDW propagation vector at Cu L3-resonance at 70 and 250 K. At resonance, the scattering factor becomes complex (fi′+ifi′) and strongly depends on the valence state of the resonating Cu atoms. CDW correlations give rise to the additional intensity observed at 70 K (red squares). The non-monotonic background does not change at temperatures above 200 K. The inset shows the total X-ray fluorescence spectrum (XAS) at 70 K. Arrows indicate the energies at which the momentum scans in a and b were performed. (b) The CDW peak at 70 K is not observed off resonance. (c) Intensity difference between scans at 70 and 250 K and fit to a Gaussian function (solid line). Scans along H and K were found to be equivalent, as expected for the tetragonal structure of Hg1201. (d) RIXS spectra at the Cu L3-edge (931.7 eV) obtained with the polarization vector perpendicular to the scattering plane (σ-polarization). Excitations typical of the cuprates are identified. The insets are zooms (red frame) for 75 and 220 K at three values of Q around the CDW wave vector. The enhancement of the quasi-elastic peak due to the CDW is observed for HCDW≈0.28 r.l.u. The spectra are normalized to the d–d excitation intensity. (e) Integrated intensity of the quasi-elastic peak as a function of H at 75 and 220 K. Data are fit to a Gaussian peak with a parabolic background. The peak widths in c and e correspond to correlation length values of ξCDW/a=5.5(8) and 4.6(2), respectively.
