Structural and mechanical properties of stable and metastable phases in SixGe1-x alloys
Bibliographic record
Abstract
Stabilization of metastable phases of silicon-germanium alloys are of both fundamental and applied interest. By combining experimental and theoretical approaches, we investigated different Si x Ge 1-x compositions (x = 0.5 and 0.3) under high-pressure (HP) conditions. Homogeneous Ge-dominant Si x Ge 1-x alloys are difficult to synthesize, which explains the paucity of literature on the subject. Such Ge-rich alloys were obtained by combining arc melting and solid-state synthesis. Then, in situ HP X-ray diffraction experiments were performed. During HP cycling, the investigated Si x Ge 1-x alloys follow a similar phase transition pathway of Si and Si-rich binaries. On compression, the stable cubic semiconducting phase transforms to the tetragonal β-tin metallic phase at around 10 GPa. Under decompression, the metallic β-phase first transforms to the rhombohedral r8 phase. After further decompression, the rhombohedral phase partially transforms to the body-centered cubic bc8 phase. Both r8- and bc8-phases coexist at ambient conditions in the recovered sample. The experimental results are compared with density functional theory simulations and discussed in relation with the previous published results on Si-rich alloy (Si 0.8 Ge 0.2 ). This allows giving an overview of the structural and mechanical properties of different phases as well as the phase stability as a function of the concentration in Si x Ge 1-x alloys. This opens the way to select composition and phases to tune some physical properties. • Large scale synthesis of Ge-rich Si-Ge alloys (Si 0.5 Ge 0.5 and Si 0.3 Ge 0.7 ). • Experimental and numerical studies of these alloys at high-pressure. • Determination of the phase stability of these alloys. • Dependence of structural and mechanical properties on the composition of Si-Ge alloys. • Thermodynamic models of the pressure dependence of phase transitions on composition.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| 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".