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 machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| 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) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".