First-principles electronic band structure investigations of five compounds of the CaO-Al2O3 family, 3CaO·Al2O3, 12CaO·7Al2O3, CaO·Al2O3, CaO·2Al2O3, and CaO·6Al2O3, as well as CaO and alpha-, theta-, and kappa-Al2O3 are performed. We find that the conduction band in the complex oxides is formed from the oxygen antibonding p states and, although the band gap in Al2O3 is almost twice larger than in CaO, the s states of both cations. Such a hybrid nature of the conduction band leads to isotropic electron effective masses which are nearly the same for all compounds investigated. This insensitivity of the effective mass to variations in the composition and structure suggests that upon a proper degenerate doping, both amorphous and crystalline phases of the materials will possess mobile extra electrons.
J. E. Medvedeva et al., "Electronic Band Structure and Carrier Effective Mass in Calcium Aluminates," Physical Review B, American Physical Society (APS), Jan 2007.
The definitive version is available at http://dx.doi.org/10.1103/PhysRevB.76.155107
University of Missouri Research Board
Keywords and Phrases
Effective Mass; Electronic Band Structure; Structure
Article - Journal
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