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Hopping Versus Bulk Conductivity In Transparent Oxides: 12cao - 7al₂O₃, Julia E. Medvedeva, Arthur J. Freeman
Hopping Versus Bulk Conductivity In Transparent Oxides: 12cao - 7al₂O₃, Julia E. Medvedeva, Arthur J. Freeman
Physics Faculty Research & Creative Works
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 Ca …
Electronic Structure And Light-Induced Conductivity Of A Transparent Refractory Oxide, Julia E. Medvedeva, Arthur J. Freeman, Mariana I. Bertoni, Thomas O. Mason
Electronic Structure And Light-Induced Conductivity Of A Transparent Refractory Oxide, Julia E. Medvedeva, Arthur J. Freeman, Mariana I. Bertoni, Thomas O. Mason
Physics Faculty Research & Creative Works
Combined first-principles and experimental investigations reveal the underlying mechanism responsible for a drastic change of the conductivity (by 10 orders of magnitude) following hydrogen annealing and UV irradiation in a transparent oxide, 12CaO · 7Al2O3, found by Hayashi et al. [Nature (London) 419, 462 (2002).] The charge transport associated with photoexcitation of an electron from H- occurs by electron hopping.We identify the atoms participating in the hops, determine the exact paths for the carrier migration, estimate the temperature behavior of the hopping transport, and predict a way to enhance the conductivity by specific doping.