Zigzag filamentary theory of broken symmetry of neutron and infrared vibronic spectra of YBa2Cu3O6+x

Abstract Filamentary high-temperature superconductor (HTSC) theory differs fundamentally from continuous HTSC theories because it emphasizes self-organized discrete dopant networks and does not make the effective-medium approximation. Analysis of neutron and infrared (especially with c-axis polarization) vibrational spectra, primarily for YBa2Cu3O6+x, within the filamentary framework, shows that the observed vibronic anomalies near 400 cm−1 (50meV) are associated with curvilinear filamentary paths. These paths pass through the cuprate chains and planes, as well as resonant tunnelling centres in the BaO layers. The analysis and the data confirm earlier filamentary structural models containing ferroelastic domains of diameter 3–4 nm in the CuO2 planes; it is these nanodomains that are responsible for the discrete glassy nature of both electronic and vibrational properties. Chemical trends in vibronic energies and oscillator strengths, for both neutron and photon scattering, that were anomalous in continuum models, are readily explained by the filamentary model.