Fluctuating Bond Model of cuprate superconductivity.

The fluctuating bond model(FBM),an empirical model based on a strong,local coupling of electrons to the square of the planar oxygen vibrator amplitudes, provides explainations of the d-wave pairing mechanism\footnote{Nature phys. 3, 184-191 (2007)} and the pseudogap\footnote{Phys. Rev. B 83, 144503 (2011)} of cuprate superconductivity. The d-wave pairing is mediated by the anharmonic phonon (planar oxygen vibrator) which is also responsible for the pseudogap when the C4 symmetry of the oxygen vibrator is broken. Here we present calculations of gap and T{\_}c in a unitary framework involving pseudogap as a competing order parameter, with the help of ab initio simulations.