First-principles calculations of the mayenite-based oxide, [Ca12Al14O32]2+(2e-), reveal the mechanism responsible for its high conductivity. A detailed comparison of the electronic and optical properties of this material with those of the recently discovered transparent conducting oxide, H-doped UV-activated Ca12Al14O33, allowed us to conclude that the enhanced conductivity in [Ca12Al14O32]2+(2e-) is achieved by elimination of the Coulomb blockade of the charge carriers. This results in a transition from variable range-hopping behavior with a Coulomb gap in H-doped UV-irradiated Ca12Al14O33, to bulk conductivity in [Ca12Al14O32]2+(2e-). Further, the high degree of delocalization of the conduction electrons obtained in [Ca12Al14O32]2+(2e-) indicates that it cannot be classified as an electride, as originally suggested.
J. E. Medvedeva and A. J. Freeman, "Hopping versus bulk conductivity in transparent oxides: 12CaO - 7Al 2O 3," Applied Physics Letters, vol. 85, no. 6, pp. 955-957, American Institute of Physics (AIP), Aug 2004.
The definitive version is available at http://dx.doi.org/10.1063/1.1781362
Keywords and Phrases
Absorption Peaks; Atomic Sphere Approximation; Charge Density; Electron Hopping; Band Structure; Boundary Conditions; Coordination Reactions; Electric Charge; Electric Conductivity; Electron Transport Properties; Electronic Density Of States; Electronic Properties; Light Absorption; Negative Ions; Optical Properties; Optoelectronic Devices; Calcium Compounds
International Standard Serial Number (ISSN)
Article - Journal
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