Experimental and first-principles investigation of the electronic structure anisotropy of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="normal">Cr</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:mtext>AlC</mml:mtext></mml:math>
Bibliographic record
Abstract
The anisotropy of the electronic structure of the $\mathit{MAX}$ phase ${\mathrm{Cr}}_{2}\mathrm{AlC}$ has been investigated by electron-energy-loss spectroscopy (EELS) at the C $K$ edge, and x-ray-absorption spectroscopy (XAS) at the Al $K$, Cr ${L}_{2,3}$, and Cr $K$ edges. The experimental spectra were interpreted using either a multiple-scattering approach or a full-potential band-structure method. The anisotropy is found to be small around C atoms because of the rather isotropic nature of the octahedral site, and of the averaging of the empty C $p$ states probed by EELS at the C $K$ edge. In turn, a pronounced anisotropy of the charge distribution around Al atoms is evidenced from polarized XAS measurements performed on textured ${\mathrm{Cr}}_{2}\mathrm{AlC}$ sputtered thin films. From the analysis of the XAS data using the multiple-scattering feff code, it is demonstrated that the probed thin film is constituted of $70%$ (0001) and $30%$ $(10\overline{1}3)$ grains oriented parallel to the film surface. A decomposition of the calculated spectrum in coordination shells allows for the ability to connect XAS fine structures to the ${\mathrm{Cr}}_{2}\mathrm{AlC}$ structure. Combining high-resolution data with up-to-date multiple-scattering calculations, it is shown that the crystalline orientations of the grains present in a probe of $100\ifmmode\times\else\texttimes\fi{}100$ $\ensuremath{\mu}\mathrm{m}{}^{2}$ can be determined from the Cr $K$ edge. Interestingly, it is also revealed that a static disorder is involved in the studied thin films. These findings highlight that, given the overall agreement between experimental and calculated spectra, the ${\mathrm{Cr}}_{2}\mathrm{AlC}$ electronic structure is accurately predicted using density functional theory.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.016 | 0.001 |
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".