Electron pairs' sliding states

A model of Cu-O-Cu-O four-center four-electron part of the copper-oxide plane embedded in a superconducting crystal lattice (LSCO) is considered. It is shown that shifting lattice atoms in the nearest-neighbor plane by a distance as small as 0.05 A from their equilibrium position may trigger a dramatic change of the ground state electronic charge distributions in the CuOCuO chain leading to electron pairs' concerted sliding over distances as large as about 2 A , i.e. close to the copper-oxide atomic distance. The sliding effect stems from electronic states' avoided crossings with the appearance of the corresponding energy gaps, and depends crucially on the lattice crystal field and doping.