Superconducting critical temperature, oxygen ordering and devil's staircase in YBa 2Cu 3O 6+ [formula omitted

Abstract

Using the appropriate extension of the three-band Hubbard model to describe the basal CuO 2+ x subsystem of YBa 2Cu 3O 6+ x , for a certain region of parameters we obtain: a) the number of holes n H in the superconducting planes and T c as a function of x have a plateau, b) using a structural model to include the effect of interatomic OO repulsions, there is a transition from structures without first or second nearest-neighbor O atoms (HS) to order in chains (CS) at x ∼ 0.45 for increasing x . We also study the structural model for values of x for which the CS are stable.