Temperature-independent anomalous Hall effect and magnetic field angular dependence in thin bismuth electronic devices
Bibliographic record
Abstract
A requirement to observe the anomalous Hall effect (AHE) in an electronic system is for it to break time-reversal symmetry, such as for example in materials that are ferromagnetic. In this work, making use of a newly-developed mechanical exfoliation technique, we have fabricated thin electronic devices in diamagnetic bismuth and performed electronic transport experiments over a wide range of temperatures and magnetic fields. In a 68 nm thick bismuth device, we unequivocally observe an AHE that surprisingly was observed to be entirely temperature independent from 15 mK to 300 K temperatures. In addition, the longitudinal resistance was observed to be entirely featureless, i.e., exhibited no quantum oscillations or magnetoresistance for magnetic fields up to ± 30 T. These observations suggest there could be a hidden mechanism responsible for time-reversal symmetry breaking in bismuth and this could be of fundamental importance considering recent compelling evidence for bismuth to be a higher-order topological insulator.
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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 | 0.000 |
| 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) | 0.001 | 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".