Evidence for optimal isometric bond order in high-temperature superconductors

Abstract

Critical results from chemical structure studies of high-temperature superconductors are elucidated which show a tendency toward isometric bond order which correlates positively with increasing critical temperature. Evidence from phonon, interstitial charge density, oxygen ordering and pressure effects, and lattice instability studies is summarized, and congruence with configuration interaction symmetry and bipolaron models is noted. Prospective high-temperature superconductors are identified.