First principles study of hydrogen in lead zirconate titanate
Bibliographic record
Abstract
Abstract Lead zirconate titanate (PZT) is a widely used piezoelectric and ferroelectric material with applications ranging from actuators in fuel injectors to ferroelectric random-access memories. Hydrogen is known to cause degradation in most metals through a ductile-to-brittle transformation called hydrogen embrittlement. Similarly, piezoelectric materials have also been found to degrade through hydrogen exposure, not only due to embrittlement, but also through reduced polarity and Pb migration. This gives rise to the need of understanding the behavior of hydrogen in piezoelectric material. This research presents the initial results of a study which aims to simulate hydrogen diffusion in PZT using multi-scale simulation techniques. First-principles calculations were done to determine the possible hydrogen occupancy locations in the PZT lattice. For these locations we calculated the effect on polarization and the dimensions of the PZT lattice by dissolved hydrogen and predicting paths available for the escape of hydrogen atoms. These results will serve as a basis for future nudged elastic band calculations to determine the diffusion characteristics for the individual diffusion steps, which can in turn be used to predict the bulk diffusion characteristics with kinetic Monte Carlo simulations.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".