Flat band induced quantum criticality in a nonsuperconducting iron pnictide
Bibliographic record
Abstract
Flat electronic bands at the Fermi energy $({E}_{\mathrm{F}})$ can induce interaction-driven instabilities and further result in the emergence of a plethora of new quantum phases such as Mott insulators, ferromagnetism, fractional quantum Hall states even at high temperatures, and superconductivity. Except for flat bands in $f$-electron systems and special geometric lattices, however, the materials with quantum criticality induced by flat bands just at ${E}_{\mathrm{F}}$ remain elusive. Here, by using angle-resolved photoemission spectroscopy and band structure calculations, we present a comprehensive study of the low-energy electronic structure of a nonsuperconducting iron pnictide, $\mathrm{Ba}{({\mathrm{Fe}}_{1/3}{\mathrm{Co}}_{1/3}{\mathrm{Ni}}_{1/3})}_{2}{\mathrm{As}}_{2}$, which is a quantum-critical $3d$ transition metal alloy. We demonstrate the existence of a dispersionless flat band of ${t}_{2g}$ orbitals just at ${E}_{\mathrm{F}}$ which is responsible for quantum critical behaviors. Our findings will promote studies of emergent physics induced by flat bands, such as non-Fermi-liquid behaviors and quantum critical phenomena in $3d$ transition metals.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.000 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.002 |
| Insufficient payload (model declined to judge) | 0.001 | 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".