A first-principles study of the effect of vacancy defects on the electronic structures of greigite (Fe3S4)
Bibliographic record
Abstract
) is a ferrimagnetic mineral with an inverse spinel structure. Besides its importance in the bio-geochemical cycle, it also has great potential applications for its unique properties such as its half metallic electronic structure at ambient condition. However, it has been challenging to get high purity and crystallinity samples of greigite in experiment, and the defect effect on the electronic structure of greigite was not clear. In the present study, first-principles calculations have been performed to investigate the ground state electronic structure of greigite with monovacancy. It is found that, with an vacancy concentration lower than 3.6%, the greigite with an Fe vacancy is an insulator with charge orderings, while the greigite with a S vacancy becomes a half-metal and has a magnetic moment of <4.0 μB per formula unit. The present result helps to understand the absence of the Verwey transition and the magnetic property of greigite measured in experiment. The understanding of the electronic structure of defective greigite could also be utilized to manipulate the properties of greigite for spintronic applications.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 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) | 0.002 | 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".