Data for BCZY

This dataset supports an ab initio thermodynamic study of phase stability in the proton-conducting perovskite solid solution BaCe0.75−xZrxY0.25O2.875 (x = 0–0.75), with fixed yttrium and oxygen-vacancy concentrations. For each Zr concentration, the lowest-energy cation–vacancy configuration was identified using density functional theory (DFT) combined with a genetic-algorithm (GA) configurational search on a 2×2×2 perovskite supercell. Temperature-dependent Gibbs free energies were evaluated within the harmonic approximation using phonon calculations, enabling a discrete convex-hull analysis among the sampled compositions. The dataset contains: (i) the GA-selected relaxed structures (POSCAR) for the seven compositions BCZY06, 15, 24, 33, 42, 51, and 60; (ii) computed DFT total energies and convex-hull energy data; (iii) phonon data (Phonopy force sets/force constants and thermal-property outputs); and (iv) the DFT calculation settings used. These data reproduce the stability crossover reported near 790 K and the finite-temperature phase-stability map presented in the associated article.