Optical determination of the superconducting energy gap in electron-doped<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mi mathvariant="normal">Pr</mml:mi><mml:mn>1.85</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">Ce</mml:mi><mml:mn>0.15</mml:mn></mml:msub><mml:mi mathvariant="normal">Cu</mml:mi><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:mrow></mml:math>
Bibliographic record
Abstract
The optical properties of single crystal ${\mathrm{Pr}}_{1.85}{\mathrm{Ce}}_{0.15}\mathrm{Cu}{\mathrm{O}}_{4}$ have been measured over a wide frequency range above and below the critical temperature $({T}_{c}\ensuremath{\simeq}20\phantom{\rule{0.3em}{0ex}}\mathrm{K})$. In the normal state the coherent part of the conductivity is described by the Drude model, from which the scattering rate just above ${T}_{c}$ is determined to be $1∕\ensuremath{\tau}\ensuremath{\simeq}80\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$. The condition that $\ensuremath{\hbar}∕\ensuremath{\tau}\ensuremath{\approx}2{k}_{B}T$ near ${T}_{c}$ appears to be a general result in many of the cuprate superconductors. Below ${T}_{c}$ the formation of a superconducting energy gap is clearly visible in the reflectance, from which the gap maximum is estimated to be ${\ensuremath{\Delta}}_{0}\ensuremath{\simeq}35\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ $(4.3\phantom{\rule{0.3em}{0ex}}\mathrm{meV})$. The ability to observe the superconducting energy gap in the optical properties favors the nonmonotonic over the monotonic description of the $d$-wave gap. The penetration depth for $T⪡{T}_{c}$ is $\ensuremath{\lambda}\ensuremath{\simeq}2000\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$, which when taken with the estimated value for the dc conductivity just above ${T}_{c}$ of ${\ensuremath{\sigma}}_{dc}\ensuremath{\simeq}35\ifmmode\times\else\texttimes\fi{}{10}^{3}\phantom{\rule{0.3em}{0ex}}{\ensuremath{\Omega}}^{\ensuremath{-}1}\phantom{\rule{0.2em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ places this material on the general scaling line for the cuprates defined by $1∕{\ensuremath{\lambda}}^{2}\ensuremath{\propto}{\ensuremath{\sigma}}_{dc}(T\ensuremath{\simeq}{T}_{c})∙{T}_{c}$. These results are consistent with the observation that $1∕\ensuremath{\tau}\ensuremath{\approx}2{\ensuremath{\Delta}}_{0}$, which implies that the material is not in the clean limit.
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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 | 0.000 |
| 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) | 0.002 | 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".