Electronic and structural properties of bulk {gamma}-Al{sub 2}O{sub 3}

Journal Article · Thu May 01 04:00:00 EDT 1997 · Journal of the American Ceramic Society

OSTI ID:512058

Mo, S D; Xu, Y N; Ching, W Y ^[1]

---

1. Univ. of Missouri, Kansas City, MO (United States). Dept. of Physics

{gamma}-Al{sub 2}O{sub 3} 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, the authors have concluded that cation vacancies are preferentially located at the octahedral sites in bulk {gamma}-Al{sub 2}O{sub 3}. The calculation shows that the electronic structure of {gamma}-Al{sub 2}O{sub 3} differs from that of {alpha}-Al{sub 2}O{sub 3} in fine details. {gamma}-Al{sub 2}O{sub 3} has a smaller band gap and wider valence bandwidths. The calculated density of states (DOS) of {gamma}-Al{sub 2}O{sub 3} 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.

• Sponsoring Organization: USDOE, Washington, DC (United States); Missouri Univ., Columbia, MO (United States)
• DOE Contract Number: FG02-84ER45170
• OSTI ID: 512058
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 5 Vol. 80; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
CERAMICS
ELECTRONIC STRUCTURE
ENERGY GAP
EVALUATED DATA
THEORETICAL DATA
VACANCIES