Nanoscopic Filters as the Origin of d Wave Energy Gaps

A ferroelastic nanoscopic checkerboard pattern of pseudo- and superconductive gaps has been resolved by scanning tunneling microscopy on BSCCO. Using this pattern one can derive [not assume] a macroscopic anisotropic d wave superconductive energy gap that agrees well with angle-resolved photoemission and Fourier transform scanning tunneling microscopy data. The derivation is orbital only [no spins], it explains chemical trends in Raman scattering peak positions and strengths, and it predicts an unexpected reversal of anisotropic Raman gap signatures between BSCCO and LSCO, in good agreement with experiment.