Phases Transformations in Nanostructures and Development of Ceramics and Metallics...
| Full text | |
| Author(s): |
Total Authors: 2
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| Affiliation: | [1] Univ Fed Maranhao, BR-65700000 Bacabal, Maranhao - Brazil
[2] Univ Estadual Campinas, UNICAMP, Inst Fis Gleb Wataghin, BR-13083859 Sao Paulo - Brazil
Total Affiliations: 2
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| Document type: | Journal article |
| Source: | Journal of Applied Physics; v. 115, n. 6 FEB 14 2014. |
| Web of Science Citations: | 1 |
| Abstract | |
We study the transformations between amorphous phases of Si through molecular simulations using the environment dependent interatomic potential (EDIP) for Si. Our results show that upon pressure, the material undergoes a transformation from the low density amorphous (LDA) Si to the high density amorphous (HDA) Si. This transformation can be reversed by decompressing the material. This process, however, exhibits clear hysteresis, suggesting that the transformation LDA <-> HDA is first-order like. The HDA phase is predominantly five-fold coordinated, whereas the LDA phase is the normal tetrahedrally bonded amorphous Si. The HDA phase at 400 K and 20 GPa was submitted to an isobaric annealing up to 800 K, resulting in a denser amorphous phase, which is structurally distinct from the HDA phase. Our results also show that the atomic volume and structure of this new amorphous phase are identical to those of the glass obtained by an isobaric quenching of the liquid in equilibrium at 2000 K and 20 GPa down to 400 K. The similarities between our results and those for amorphous ices suggest that this new phase is the very high density amorphous Si. (C) 2014 AIP Publishing LLC. (AU) | |
| FAPESP's process: | 13/08293-7 - CCES - Center for Computational Engineering and Sciences |
| Grantee: | Munir Salomao Skaf |
| Support type: | Research Grants - Research, Innovation and Dissemination Centers - RIDC |