Pressure-driven suppression of the Jahn–Teller effects and structural changes in cupric oxide
Bibliographic record
Abstract
Multiferroics have been of interest as materials for use in data storage due to their coexisting ferroelectric and ferromagnetic properties. The properties of cupric oxide have been studied at pressures below 70 GPa, and it has even been suggested that it may be a room temperature multiferroic at pressures of 20 to 40 GPa. However, the properties of cupric oxide above these pressures have yet to be thoroughly examined. Here, we investigate changes in the crystal structure of cupric oxide via first principles methods. We find that the crystal structure transforms from a monoclinic structure at low pressure to a face-centred cubic and body-centred cubic structure at high pressure. We also find that the magnetic ordering switches from antiferromagnetic in the monoclinic phase to net zero magnetic moment in the face-centred cubic phase and ferromagnetic in the body-centred cubic phase. This shift in magnetic ordering is due to the superexchange interactions and Jahn-Teller instabilities, or the lack of thereof, arising from the d-orbital electrons of the cupric ions, which disrupt the mechanical stability of other possible magnetic orderings.
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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".