Data for BCZY

Description

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.

Steps to reproduce

1. Configurational search: for each Zr concentration x, enumerate symmetry-inequivalent cation–vacancy configurations on a 2×2×2 perovskite supercell (eight B-site cations, fixed Y and oxygen-vacancy content) and identify the lowest-energy arrangement using a genetic-algorithm search ranked by 0 K DFT total energy. 2. DFT calculations: perform structure relaxations and total-energy evaluations in VASP [state functional (e.g., PBEsol), plane-wave cutoff, k-point mesh, and PAW POTCAR versions as listed in dft_settings/]. 3. Phonon calculations: compute harmonic phonons with Phonopy using the finite-displacement method; apply a 50 cm⁻¹ imaginary-frequency cutoff for soft modes; evaluate temperature-dependent vibrational free energies within the harmonic approximation. 4. Stability analysis: combine DFT energies with vibrational free energies to obtain Gibbs free energies, then perform a discrete convex-hull analysis across the sampled compositions to determine the most stable phase as a function of temperature.

Institutions

• Korea University of Technology and Education

  Chungcheongnam-do, Cheonan
• Korea Institute of Science and Technology

  Seoul, Seoul

Categories

Licence