Temperature and Dynamical Effects on the High-Pressure Cubic-Diamond ↔ β-Tin Phase Transition in Si and Ge
✍ Scribed by K. Gaál-Nagy; A. Bauer; M. Schmitt; K. Karch; P. Pavone; D. Strauch
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 227 KB
- Volume
- 211
- Category
- Article
- ISSN
- 0370-1972
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✦ Synopsis
The cubic-diamond 6 b-tin phase transition in Si and Ge is studied using modern first-principles techniques based on density-functional theory (DFT) without making use of any experimental inputs. The relevant Gibbs energies, GpY T U À TS pV, are obtained in the quasi-harmonic approximation from static internal energies and free-energy vibrational contributions in the two different phases, as computed by DFT and density-functional perturbation theory (DFPT), respectively. Our results show that the combination of the quasi-harmonic approximation and DFPT provides an efficient tool for the study of finite-temperature pressure-induced solid±solid phase transformations.