Electronic band structure and carrier effective mass in calcium aluminates
| Autor: | M. D. Hoffman, Julia E. Medvedeva, Emily N. Teasley |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Physics
Condensed Matter - Materials Science Band gap Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences Condensed Matter Physics Antibonding molecular orbital Electronic Optical and Magnetic Materials chemistry.chemical_compound Crystallography Effective mass (solid-state physics) chemistry Calcium aluminates Atomic physics Electronic band structure Conduction band |
| Zdroj: | Physical Review B. 76 |
| ISSN: | 1550-235X 1098-0121 |
| Popis: | First-principles electronic band structure investigations of five compounds of the $\mathrm{Ca}\mathrm{O}\text{\penalty1000-\hskip0pt}{\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ family, $3\mathrm{Ca}\mathrm{O}∙{\mathrm{Al}}_{2}{\mathrm{O}}_{3}$, $12\mathrm{Ca}\mathrm{O}∙7{\mathrm{Al}}_{2}{\mathrm{O}}_{3}$, $\mathrm{Ca}\mathrm{O}∙{\mathrm{Al}}_{2}{\mathrm{O}}_{3}$, $\mathrm{Ca}\mathrm{O}∙2{\mathrm{Al}}_{2}{\mathrm{O}}_{3}$, and $\mathrm{Ca}\mathrm{O}∙6{\mathrm{Al}}_{2}{\mathrm{O}}_{3}$, as well as CaO and $\ensuremath{\alpha}$-, $\ensuremath{\theta}$-, and $\ensuremath{\kappa}\text{\penalty1000-\hskip0pt}{\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ 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 ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ 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. |
| Databáze: | OpenAIRE |
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