Oxygen Isotope Effect in the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>a</mml:mi><mml:mi>b</mml:mi></mml:math>-Plane Reflectance of Underdoped<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="normal">Y</mml:mi><mml:mi mathvariant="normal">B</mml:mi><mml:msub><mml:mi mathvariant="normal">a</mml:mi><mml:mn mathvariant="normal">2</mml:mn></mml:msub><mml:mi mathvariant="normal">C</mml:mi><mml:msub><mml:mi mathvariant="normal">u</mml:mi><mml:mn mathvariant="normal">3</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mrow><mml:mn mathvariant="normal">7</mml:mn><mml:mo mathvariant="normal">−</mml:mo><mml:mi mathvariant="normal">δ</mml:mi></mml:mrow></mml:msub></mml:math>
Bibliographic record
Abstract
We have measured the effect of oxygen isotope substitution on the $ab$-plane reflectance of underdoped $\mathrm{Y}\mathrm{B}{\mathrm{a}}_{\mathrm{2}}\mathrm{C}{\mathrm{u}}_{\mathrm{3}}{\mathrm{O}}_{\mathrm{7}\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\delta}}}$. The frequency shift of the transverse optic phonons due to the substitution of $^{\mathrm{16}}\mathrm{O}$ by $^{\mathrm{18}}\mathrm{O}$ yields an isotope effect of the expected magnitude for copper-oxygen stretching modes with $\ensuremath{\alpha}=0.5\ifmmode\pm\else\textpm\fi{}0.1$. The reflectance shoulder at $400--500\text{ }\mathrm{c}{\mathrm{m}}^{\mathrm{\ensuremath{-}}\mathrm{1}}$ shows a much smaller exponent of $\ensuremath{\alpha}=0.1\ifmmode\pm\else\textpm\fi{}0.1$ in the normal state and $\ensuremath{\alpha}=0.23\ifmmode\pm\else\textpm\fi{}0.1$ in the superconducting state. These observations suggest that the shoulder is of electronic origin and not due to a phonon mode as has been suggested recently.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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) | 0.017 | 0.002 |
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".