Theoretical investigation of the electronic structure and transport properties of Na<sub>1+<i>x</i></sub>Co<sub>2</sub>O<sub>4</sub>
Bibliographic record
Abstract
The validity of a simple band description for explaining the unexpectedly large thermopower in Na1+xCo2O4 was investigated. Non-spin-polarized and spin-polarized electronic structures of layered cobalt oxides Na1+xCo2O4 are studied by means of first-principles density functional theory calculations. The fractional occupancy of Na is described via two approaches--the virtual crystal approximation and the rigid band model. We also found that the band structure of the valence band is very sensitive to the geometry of the CoO6 'octahedron', and cannot be described by a simple crystal field model. The Seebeck coefficients are calculated from the standard kinetic theory. The calculated thermopower demonstrates the importance of a high density of states close to the Fermi level. The calculated Seebeck coefficient based on the paramagnetic band structure is apparently in good agreement with experimental observation although it has been suggested that spin entropy may dominate the thermopower. However, the calculation failed to account for the observed negative in-plane Hall coefficient.
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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".