Phonon anomalies and lattice dynamics in superconducting oxychlorides Ca${}_{2-x}$CuO${}_2$Cl

Abstract

We present a comprehensive study of the phonon dispersion in an underdoped, superconducting Ca${}_{2-x}$CuO${}_2$Cl${}_2$ crystal. We interpret the results using lattice dynamical calculations based on a shell model, and we compare the results, to other hole-doped cuprates, in particular to the ones isomorphic to La${}_{2-x}$Sr${}_x$CuO${}_4$ (LSCO). We found that an anomalous dip in the Cu-O bond stretching dispersion develops in oxychlorides with a simultaneous marked broadening of the mode. The broadening is maximum at $\approx (\pi /(2a)00)$ that corresponds to the charge-modulations propagation vector. Our analysis also suggests that screening effects in calculations may cause an apparent cosine-shaped bending of the Cu-O bond-stretching dispersion along both the ($q$ 0 0) and ($q$ $q$ 0) directions, that is not observed on the data close to optimal doping. This observation suggests that the discrepancy between experimental data and \textit{ab-initio} calculations on this mode originates from an overestimation of the doping effects on the mode.

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Cited by in corpus (7)

• Incommensurate phonon anomaly and the nature of charge density waves in cuprates
• Evidence for a charge collective mode associated with superconductivity in copper oxides from neutron and x-ray scattering measurements of La${}_{2-x}$Sr${}_x$CuO${}_4$
• Introduction to High-Resolution Inelastic X-Ray Scattering
• Resonant inelastic X-ray scattering study of spin-wave excitations in the cuprate parent compound Ca${}_2$CuO${}_2$Cl${}_2$
• Three interaction energy scales in single-layer high-T${}_C$ cuprate HgBa${}_2$CuO${}_{4+\delta }$
• Phonon anomalies with doping in superconducting oxychlorides Ca2-xCuO2Cl2
• Bulk charge density wave and electron-phonon coupling in superconducting copper oxychlorides