Evidence of a ZnCr<sub>2</sub>Se<sub>4</sub> Spinel Inclusion at the Core of a Cr-Doped ZnSe Quantum Dot
Bibliographic record
Abstract
Herein we report doping of ZnSe by Cr ions leads to formation of small ZnCr(2)Se(4) spinel inclusions within the cubic sphalerite lattice of a 2.8 nm CrZnSe quantum dot (QD). The Cr ion incorporates as a pair of Cr(III) ions occupying edge-sharing tetragonal distorted octahedral sites generated by formation of three Zn ion vacancies in the sphalerite lattice in order to charge compensate the QD. The site is analogous to the formation of a subunit of the ZnCr(2)Se(4) spinel phase known to form as inclusions during peritectoid crystal growth in the ternary CrZnSe solid-state compound. The oxidation state and site symmetry of the Cr ion is confirmed by X-ray absorption near edge spectroscopy (XANES), crystal field absorption spectroscopy, and electron paramagnetic resonance (EPR). Incorporation as the Cr(III) oxidation state is consistent with the thermodynamic preference for Cr to occupy an octahedral site within a II-VI semiconductor lattice with a half-filled t(2g) d-level. The measured crystal field splitting energy for the CrZnSe QD is 2.08 eV (2.07 eV form XANES), consistent with a spinel inclusion. Further evidence of a spinel inclusion is provided by analysis of the magnetic data, where antiferromagnetic (AFM) exchange, a Curie-Weiss (C-W) temperature of θ = -125 K, and a nearest-neighbor exchange coupling constant of J(NN) = -12.5 K are observed. The formation of stable spinel inclusions in a QD has not been previously reported.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.002 |
| 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".