Increasing superconducting<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>T</mml:mi></mml:mrow><mml:mrow><mml:mi>c</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>’s by a factor of 1000 with large hopping anisotropies in two-dimensional<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>t</mml:mi><mml:mo>−</mml:mo><mml:mi>J</mml:mi></mml:math>model systems
Bibliographic record
Abstract
We have studied the enhancement of the superconducting transition temperature ${T}_{c}$ in a $t\ensuremath{-}J\ensuremath{-}U$ model of electrons moving on a square lattice in which anisotropic electronic hopping is introduced. For this model we have calculated ${T}_{c}$ for singlet pairing using the non-self-consistent Thouless criterion, and find a dramatic enhancement of ${T}_{c}$ induced by large hopping anisotropies. Further, the maximum increase in ${T}_{c}$ is obtained when the system is pushed towards the extreme anisotropy limit, that is, when the hopping of electrons is confined to occur in only one dimension, while superexchange couples the electrons both parallel and perpendicular to the direction in which hopping occurs. We demonstrate that in this limit the increase in ${T}_{c},$ with respect to the isotropic system, can be of the order of 1000. We have also determined that in the extreme anisotropy limit the superconducting gap is an equal mixture of s and d pairing symmetries (two choices of such a combination being $s+d$ and $s+id)$ owing to the reduced (square to rectangular) symmetry of the system in the presence of hopping anisotropies. Thus the presence of d-wave superconducting features in materials whose symmetry is very different from that of a two-dimensional square lattice is not unexpected.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.002 | 0.004 |
| Meta-epidemiology (broad) | 0.001 | 0.004 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.002 | 0.003 |
| Scholarly communication | 0.002 | 0.005 |
| Open science | 0.003 | 0.003 |
| Research integrity | 0.003 | 0.004 |
| Insufficient payload (model declined to judge) | 0.165 | 0.005 |
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".