Giant Electron-Phonon Anomaly in Doped La₂CuO₄and Other Cuprates

Figure 27

LO phonon dispersions in Bi₂Sr_1.6La_0.4Cu₂O_6+x [78]. (a) IXS spectra for 𝐐=(3+𝜉,0,0) with ξ from the BZ center (top spectrum, ξ = 0.02) to the BZ boundary (bottom spectrum, ξ = 0.45). The spectra are vertically shifted. The solid lines show the harmonic oscillator fit, the dashed lines show the elastic tail and the dotted lines show the two modes used in the fit. (b,c) Phonon dispersions and linewidths. The cosine dashed lines are guides for the eye illustrating the crossing (b) and anticrossing (c) scenarios. (d) Full width at half maximum. The error bars are an estimate of the standard deviation of the fit coefficients.