High‐Pressure Stability and Electronic Properties of Sodium‐Rich Nitrides: Insights from First‐Principles Calculations
Bibliographic record
Abstract
Abstract Using first‐principles structure search calculations, we investigated the phase stability of sodium‐nitrogen (Na−N) compounds under high pressure. Our study reveals that increasing pressure promotes the formation of Na‐rich nitrides, leading to the prediction of three previously unreported stoichiometries: Na 2 N, Na 5 N, and Na 8 N. Notably, the electride Na 5 N undergoes a pressure‐induced structural transition from a P 6/ mmm to a P 6 3 / mmc phase. This transformation is characterized by spatial reorientation and redistribution of interstitial anionic electrons (IAEs). In the P 6 3 / mmc phase, IAEs adopt a zero‐dimensional, triangular‐like configuration, whereas in the low‐pressure P 6/ mmm phase, they form an interconnected, graphene‐like network. With increasing pressure, P 6 3 / mmc phase undergoes a transition from metallic to semiconducting behavior due to the increased interaction between sodium and IAEs. Additionally, C 2/ m Na 8 N, featuring triangular‐ and ship‐like IAEs, is predicted to exhibit superconductivity. Our findings provide new insights into the behavior and stability of Na‐rich nitrides under high‐pressure conditions.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".