High-temperature large-gap quantum anomalous Hall insulating state in ultrathin double perovskite films
Bibliographic record
Abstract
Towards the goal of realizing topological phases in thin films of correlated oxide and heterostructures, we propose here a quantum anomalous Hall insulator (QAHI) in ultrathin films of double perovskites based on mixed $3d\ensuremath{-}5d$ or $3d\ensuremath{-}4d$ transition-metal ions, grown along the [111] direction. Considering the specific case of ultrathin ${\mathrm{Ba}}_{2}{\mathrm{FeReO}}_{6}$, we present a theoretical analysis of an effective Hamiltonian derived from first principles. We establish that a strong spin-orbit coupling at the Re site, ${t}_{2g}$ symmetry of the low-energy $d$ bands, polarity of its [111] orientation of perovskite structure, and mixed $3d\ensuremath{-}5d$ chemistry results in room temperature magnetism with a robust QAHI state of Chern number $C=1$ and a large band gap. We uncover and highlight a nonrelativistic orbital Rashba-type effect in addition to the spin-orbit coupling, that governs this QAHI state. With a band gap of $\ensuremath{\sim}100$ meV in electronic structure and magnetic transition temperature ${T}_{c}\ensuremath{\sim}300\phantom{\rule{0.28em}{0ex}}\mathrm{K}$ estimated by Monte Carlo simulations, our finding of the QAHI state in ultrathin ${\mathrm{Ba}}_{2}{\mathrm{FeReO}}_{6}$ is expected to stimulate experimental verification along with possible practical applications of its dissipationless edge currents.
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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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.003 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.001 |
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".