Spin-polaron band in the ferromagnetic heavy-fermion superconductor UGe<sub>2</sub>
Bibliographic record
Abstract
It has long been believed that coexistence among ferromagnetic ordering, superconductivity or heavy-fermion behaviour is impossible, as the former supports parallel spin alignment while the latter two phenomena assume a spin-singlet configuration. This understanding has recently been challenged by a number of observations in uranium intermetallic systems where superconductivity (SC) is found within a ferromagnetic state and both ordering phenomena are facilitated by the same set of comparatively heavy quasiparticles which bind into spin-triplet pairs in the SC state. Within the heavy-fermion scenario, this mechanism necessarily assumes that the magnetism has a band character. This band is expected to be responsible for all three phenomena – heavy-fermion behaviour, ferromagnetism and superconductivity – although its nature and the nature of the heavy quasiparticles have so far remained unclear. Our high-field muon spin rotation measurements are indicative of spin polarons of subnanometer size in UGe2. These spin polarons behave as heavy quasiparticles made of 5f electrons. Once coherence is established, they may form a narrow spin-polaron band which thus may provide a natural reconciliation of itinerant ferromagnetism with spin-triplet superconductivity and heavy-fermion behaviour.
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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 | 0.000 | 0.000 |
| 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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".