Calculated lattice and dynamic properties and defect chemistry of ternary and quaternary cuprates related to high-Tc superconductivity

Abstract

A review is given of recent atomistic simulations of the lattice and defect properties of ternary and quaternary cuprates. The theoretical methods are essentially those used previously to investigate a wide range of ceramic oxides. They involve non-empirical, two-body potentials based on the electron-gas approach to point defects in ionic and quasi-ionic materials based on the Mott–Littleton approximation. Among the properties considered are the lattice structure, phonon density of states, fundamental defect structure, nature of the electronic disorder, oxidative non-stoichiometry and defect structure associated with cation impurities. The materials included are cuprates of the type M₂CuO₄(M = La, Pr, Nd, Al), M₂CuO₃(M = Mg, Ca, Sr, Ba), Y₂Cu₂O₅, La_1.75Sr_0.25CuO₄, LaCuO₃ and Sr₂TiO₄, Sr₃Ti₂O₇, Sr₄Ti₃O₁₀ and SrTiO₃.