Electronic and Structural Properties of Bulk γ-Al2O3

Autor:	Wai-Yim Ching, Yong-Nian Xu, Shang-Di Mo
Rok vydání:	2005
Předmět:	Valence (chemistry) Band gap Chemistry Spinel Electronic structure engineering.material Ion Crystallography Computational chemistry Vacancy defect Materials Chemistry Ceramics and Composites engineering Density of states Pair potential
Zdroj:	Journal of the American Ceramic Society. 80:1193-1197
ISSN:	1551-2916 0002-7820
Popis:	γ-Al2O3 is a defective spinel phase of alumina with cation site vacancies randomly distributed. Its structure and properties are not well understood. There has been long-standing controversy as to whether the cation vacancies are located at the tetrahedral sites or the octahedral sites. Based on an empirical pair potential calculation and first-principles electronic structure studies, we have concluded that cation vacancies are preferentially located at the octahedral sites in bulk γ-Al2O3. Our calculation shows that the electronic structure of γ-Al2O3 differs from that of α-Al2O3 in fine details. γ-Al2O3 has a smaller band gap and wider valence bandwidths. The calculated density of states (DOS) of γ-Al2O3 is in good agreement with recent experimental XPS and XES data. Site- and orbital-resolved partial DOS (PDOS) of Al atoms shows significant dependence on the local coordinations. The PDOS of an oxygen adjacent to a vacancy differs substantially from that of a fully coordinated anion.
Databáze:	OpenAIRE
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