Fig. 2: L dependence of the phonon dispersion and spectra.
From: Hybridization of lattice and charge order excitations in a superconducting cuprate
a Phonon dispersion curves of YBa2Cu3O7 along the (0 1.685 L) direction calculated by density-functional perturbation theory (lines). The phonon branches are grouped in two categories based on the symmetry operations for their displacement patterns: the first category (colored/gray lines) includes a mirror symmetry operation (σ(x), x  →   − x), while the second category (white lines) does not. Further symmetry operations are restored for the displacement patterns of some of the modes at L = 1 and 0.5 (see also discussion in the Discussion section). A colormap representation of the calculated structure factors is shown in the background. A zero value is calculated for the structure factors of the branches grouped in the second category. b, c L dependence of the experimental χ″(Q, ω) measured at b 295 K and c 12 K. A vertical offset is included for clarity. The thick solid lines correspond to the fits of the experimental data. Details of the fits are included in the lower spectra of (b) and (c) as thin lines. The fitting procedure is described in the Supplementary Note 5. The fitting results of the experimental spectra measured at 295 K are included as red open symbols in panel (a).
