Optical magnons with dominant bond-directional exchange interactions in the honeycomb lattice iridate <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>α</mml:mi><mml:mo>−</mml:mo><mml:mrow><mml:msub><mml:mi>Li</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>IrO</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>
Bibliographic record
Abstract
We have used resonant inelastic x-ray scattering to reveal optical magnons in a honeycomb lattice iridate $\ensuremath{\alpha}\ensuremath{-}{\mathrm{Li}}_{2}{\mathrm{IrO}}_{3}$. The spectrum in the energy region 20--25 meV exhibits momentum dependence, of which energy is highest at the location of the magnetic Bragg peak, $(h,k)=(\ifmmode\pm\else\textpm\fi{}0.32,0)$, and lowered toward $(0,0)$ and $(\ifmmode\pm\else\textpm\fi{}1,0)$. We compare our data with a linear spin-wave theory based on a generic nearest-neighbor spin model. We find that a dominant bond-directional Kitaev interaction of order 20 meV is required to explain the energy scale observed in our study. The observed excitations are understood as stemming from optical magnon modes whose intensity is modulated by a structure factor, resulting in the apparent momentum dependence. We also observed diffuse magnetic scattering arising from the short-range magnetic correlation well above ${T}_{N}$. In contrast to ${\mathrm{Na}}_{2}{\mathrm{IrO}}_{3}$, this diffuse scattering lacks the ${C}_{3}$ rotational symmetry of the honeycomb lattice, suggesting that the bond anisotropy is far from negligible in $\ensuremath{\alpha}\ensuremath{-}{\mathrm{Li}}_{2}{\mathrm{IrO}}_{3}$.
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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 | 0.003 | 0.002 |
| Meta-epidemiology (narrow) | 0.002 | 0.003 |
| Meta-epidemiology (broad) | 0.001 | 0.005 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.002 | 0.003 |
| Scholarly communication | 0.002 | 0.003 |
| Open science | 0.004 | 0.004 |
| Research integrity | 0.001 | 0.005 |
| Insufficient payload (model declined to judge) | 0.204 | 0.007 |
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; both teacher heads agree on what is shown here.
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".