Atomistic simulation of ionic and electronic defects in YBa2Cu3O7

The Flexible Unit Structure Engine (FUSE) for probe structure-based composition prediction

Computationally led materials discovery requires efficient methods to generate either exact or approximate crystal structures that span the composition range of a chosen phase space. Here we present a new tool, the Flexible Unit Structure Engine (FUSE), for the generation of approximate 'probe structures' to predict regions of composition space where compounds can be experimentally realised. We then test FUSE by applying it to 42 compositions in the Y3+-Sr2+-Ti4+-O2- phase field. FUSE correctly identifies all of the target compounds in the regions of stability and identifies the exact crystal structure for 8 out of the 10 compositions.

Oxygen Diffusion in La2-xSrxCuO4-δ: Molecular Dynamics Study

The oxygen mobility in La2-xSrxCuO4-δ (x=0.15; 0.6; 1) was studied by the Molecular Dynamics (MD) technique. The parent layered La2CuO4 crystal structure has been shown to give rise to a strong anisotropy of oxygen diffusion coefficient in the lattice. Equatorial oxygen sites in(CuO2) layers were found to provide the paths of the fast oxygen transport in the structure, while the axial ones in (La2O2) blocks were substantially less mobile. The influence of the dopant concentration on structural properties and energetic characteristics of the oxygen migration are discussed. Analysis of the ion trajectories obtained during the simulation allowed explaining the observed dependence of the oxygen diffusion activation energies on the strontium content and provided further insight into the mechanism of oxygen diffusion in the oxides.