  A key question in the theory of high-temperature superconductivity is whether
Off-diagonal Long-Range Order (ODLRO) can be induced wholly or in large part by
repulsive electronic correlations. Electron pairs on Cuprate and the iron-based
pnictide and chalcogenide alternant lattices may interact with a strong
short-range Coulomb repulsion and much weaker longer range attractive tail.
Here we show that such interacting electrons can cooperate to produce a
superconducting state in which time-reversed electron pairs effectively avoid
the repulsive part but reside predominantly in the attractive region of the
potential. The alternant lattice structure is a key feature of such a
stabilization mechanism leading to the occurrence of high temperature
superconductivity with dx2 -y2 or sign alternating s-wave or s plus/minus
condensate symmetries.
