Relation between superconducting transition temperature and oxygen ordering in YBa₂Cu₃O_6+x

THE superconducting transition temperature, Tc, of the ceramic high-temperature superconductor YBa2Cu3O6+xis known to depend not only on the oxygen stoichiometry x (0 < x < 1) but also on the specific ordering of the oxygen atoms in the basal CuO planes1–7. Here we present computer simulations of the formation of oxygen-ordered domains of orthorhombic structure in the basal CuO plane using a microscopic model of the oxygen ordering.

Together with a minimal-model assumption for the charge transfer, our calculations strongly suggest that it is these domains that are responsible for the characteristic variation of Tc(x). Our results lead to a theoretical prediction of Tc(x) that is in close quantitative agreement with experiments.