Tritium diffusion in a Li2TiO3 crystal terminated with the (001) surface from first-principles calculations
Autor: | Wei-Hua Wang, Kun Li, Jin-Yang Su, Wen Yang, Jia-Hong Zhu, Shu-Ping Liu, Yong-Tang Li |
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Rok vydání: | 2020 |
Předmět: |
Surface diffusion
Local density of states Materials science General Physics and Astronomy 02 engineering and technology Activation energy 021001 nanoscience & nanotechnology 01 natural sciences Molecular physics 010305 fluids & plasmas Crystal 0103 physical sciences Atom Nuclear fusion Tritium Physical and Theoretical Chemistry Diffusion (business) 0210 nano-technology |
Zdroj: | Physical Chemistry Chemical Physics. 22:27206-27213 |
ISSN: | 1463-9084 1463-9076 |
Popis: | The tritium release behavior of the Li2TiO3 crystal has become an important index to evaluate its comprehensive performance as a solid breeder material in nuclear fusion reactors. The tritium diffusion on the surface (surface diffusion) and diffusion from the inside to the surface (hopping diffusion) in Li2TiO3 crystals with a 1/3-Li(001) surface are systematically investigated by the first-principles method. Possible adsorption sites, diffusion pathways and energy barriers of surface diffusion and hopping diffusion have been calculated and analyzed, respectively. Tritium atoms are found to diffuse preferentially along the [100] direction on the surface and two equivalent pathways across the surface were identified. The obtained activation energies are about 0.50 eV for surface diffusion and 1.56 eV for hopping diffusion. The local density of states and Bader charge for typical surface diffusion and hopping diffusion pathways are calculated and analyzed. The results reveal that the tritium (T) atom bonds with neighboring oxygen (O) atoms during the surface diffusion, while the T–O interaction is significantly weakened in the hopping diffusion which results in the higher activation energy than that of surface diffusion. In combination with our previous work, a complete tritium diffusion model for the Li2TiO3 crystal is proposed and the corresponding tritium diffusion coefficients are obtained. Our obtained activation energies are in the same range as previous experimental data and could provide theoretical support for the future related experiments. |
Databáze: | OpenAIRE |
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