[1E01-03] Properties of Silicon Compounds

[1E03] First-principles calculations on substitutional solid solutions of Si oxides

*Toshiaki Nishii^1,2, Jun Onoe² (1. J-POWER, 2. Nagoya Univ.)

Keywords:thermoelectric conversion, substitutional solid solution, radioactive waste vitrification, silicon oxide, first principles calculation

From the viewpoint of high-temperature oxidation resistance, semiconductors such as solid solution of Si oxides substituted with various kinds of elements have been focused as a candidate of thermoelectric conversion materials working at a high-temperature. Since the long-term stability of the performance is considered to depend on the interaction between the matrix and the added elements, substitutional solid-solution is desired. This is the same requirement as for vitrification objects containing high-level radioactive wastes.
In this study, we performed first-principles calculations on the structures of Si oxide crystal substituted with various elements, examined the effects of the additive elements and the addition ratio on the stability of the solid-solution by comparing the bonding energy among the individual systems, and also attempted to reveal the interactions between them, which play a crucial role of determing the thermal stability, at an electronic level.