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Hopping versus bulk conductivity in transparent oxides: 12CaO.7Al2O3

J. E. Medvedeva·A. J. Freeman
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Abstract

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 novel 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 blocade 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 the delocalization of the conduction electrons obtained in [Ca12Al14O32]{2+}(2e-) indicate that it cannot be classified as an electride, originally suggested.

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J. E. Medvedeva, A. J. Freeman. 2004-04-07. Hopping versus bulk conductivity in transparent oxides: 12CaO.7Al2O3. https://doi.org/10.1063/1.1781362

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