2001 Fiscal Year Final Research Report Summary
Quantitative evaluation of vacancy formation energy in metal oxides
| Project/Area Number |
12305040
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Physical properties of metals
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
ADACHI Hirohiko Kyoto Univ., Engineering, Professor, 工学研究科, 教授 (60029105)
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| Co-Investigator(Kenkyū-buntansha) |
OGASAWARA Kazuyoshi Kyoto Univ., Engineering, Research Assoc., 工学研究科, 助手 (10283631)
NISHITANI Shigeto Kyoto Univ., Engineering, Assoc. Professor, 工学研究科, 助教授 (50192688)
TANAKA Isao Kyoto Univ., Engineering, Assoc. Prof., 工学研究科, 助教授 (70183861)
ARAKI Hideki Osaka Univ., Engineering, Assoc. Prof., 工学研究科, 助教授 (20202749)
SHIRAI Yasuharu Osaka Univ., Engineering, Professor, 工学研究科, 教授 (20154354)
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| Project Period (FY) |
2000 – 2001
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| Keywords | First principles / oxides / dopant / solute / impurity / vacancy / positron lifetime / ceramics |
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| Research Abstract |
Formation energies of neutral and charged oxygen vacancies in MgO, ZnO, A12O3, In2O3 and SnO2 have been calculated by a first principles plane-wave pseudopotential method. Two kinds of polymorphs, i.e., an ordinary phase and a high-pressure or a hypothetical negative pressure phase, have been chosen in order to see the effects of crystal structure. Theoretical calculations of vacancy-solute interactions in the selected oxides have also been examined. In conjunction to the theoretical investigations, positron lifetime experiments on Al-doped MgO samples have been made. The experiments clearly confirmed the formation of Mg-vacancies whose concentration is proportional to the amount of Al dopants, which is perfectly consistent to the theoretical predictions.
The combination of first principles calculations and positron lifetime experiments should be a very powerful tool for investigation of defects in ceramic materials in general.
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