Topology of conductive clusters in sputtered high-quality VO2 thin films on the brink of percolation threshold during insulator-to-metal and metal-to-insulator transitions
Bibliographic record
Abstract
Electrical conductivity (σ) and optical transmittance of high quality VO2 thin films deposited by DC reactive magnetron sputtering on r-cut sapphire substrates (at 650 °C) have been measured simultaneously as a function of temperature by heating and cooling scans through the phase transition region. The partial concentration of the metallic phase (Xm) has been calculated from the optical transmittance, and the σ(Xm) dependence has been analyzed through an insulator-to-metal transition (IMT) during heating and through a metal-to-insulator transition (MIT) during cooling. The results have shown to be consistent with the Efros–Shklovskii percolation theory, predicting the formation of two-dimensional infinite conductive cluster (ICC) during IMT and the preservation of three-dimensional ICC during MIT. The critical concentrations (Xc) corresponding to the appearance of ICC at IMT and the disappearance of ICC at MIT were found to be very different, 0.57 and 0.06, respectively. A mathematical model explaining very small Xc at MIT was developed. The dissimilarity of the ICC topology during IMT and MIT is connected with the appearance and disappearance of local mechanical stresses imminent in VO2 phase transitions.
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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 | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 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".