Penetration depth and gap structure in the antiperovskite oxide superconductor <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>Sr</mml:mi><mml:mrow><mml:mn>3</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:mi>SnO</mml:mi></mml:math> revealed by <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>μ</mml:mi><mml:mi>SR</mml:mi></mml:math>
Bibliographic record
Abstract
We report a $\ensuremath{\mu}\mathrm{SR}$ study on the antiperovskite oxide superconductor ${\mathrm{Sr}}_{3\ensuremath{-}x}\mathrm{SnO}$. By using transverse-field $\ensuremath{\mu}\mathrm{SR}$, we observed an increase of the muon relaxation rate upon cooling below the superconducting transition temperature ${T}_{\mathrm{c}}=5.4$ K, evidencing bulk superconductivity. The exponential temperature dependence of the relaxation rate $\ensuremath{\sigma}$ at low temperatures suggests a fully gapped superconducting state. We evaluated the zero-temperature penetration depth $\ensuremath{\lambda}(0)\ensuremath{\propto}1/\sqrt{\ensuremath{\sigma}(0)}$ to be around 320--1020 nm. Such a large value is consistent with the picture of a doped Dirac semimetal. Moreover, we established that the ratio ${T}_{\mathrm{c}}/\ensuremath{\lambda}{(0)}^{\ensuremath{-}2}$ is larger than those of ordinary superconductors and is comparable to those of unconventional superconductors. The relatively high ${T}_{\mathrm{c}}$ for small carrier density may hint at an unconventional pairing mechanism beyond the ordinary phonon-mediated pairing. In addition, zero-field $\ensuremath{\mu}\mathrm{SR}$ did not provide evidence of broken time-reversal symmetry in the superconducting state. These features are consistent with the theoretically proposed topological superconducting state in ${\mathrm{Sr}}_{3\ensuremath{-}x}\mathrm{SnO}$, as well as with ordinary $s$-wave superconductivity.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.003 | 0.004 |
| Meta-epidemiology (broad) | 0.002 | 0.005 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.003 | 0.003 |
| Scholarly communication | 0.003 | 0.004 |
| Open science | 0.005 | 0.004 |
| Research integrity | 0.003 | 0.005 |
| Insufficient payload (model declined to judge) | 0.048 | 0.006 |
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".