Enhanced electronic polarizability of metallic stripes and the universality of the bond-stretching phonon anomaly in high-temperature cuprate superconductors

Abstract

We demonstrate that the strong anomalies in the high frequency LO-phonon spectrum in cuprate superconductors can, in principle, be explained by the enhanced electronic polarizability associated with the self-organized one dimensionality of metallic stripes. Contrary to the current interpretation in terms of transversal stripe fluctuations, the anomaly should occur at momenta parallel to the stripes. The doping dependences of the anomaly are naturally explained, and we predict that the phonon linewidth and the spread of the anomaly in the transverse momentum decrease with increasing temperature, while high resolution measurements should reveal a characteristic substructure to the anomaly.