0000000000341416
AUTHOR
I Tale
Calculations of the geometry and optical properties ofFMgcenters and dimer (F2-type) centers in corundum crystals
CALCULATIONS OF THE GEOMETRY AND OPTICAL-PROPERTIES OF F-MG CENTERS AND DIMER (F-2-TYPE) CENTERS IN CORUNDUM CRYSTALS
Mechanism of self-trapped hole motion in corundum crystals
Abstract Atomistic simulations of the self-trapped hole eauilibrium geometry and migration in a pure corundum crystal have been carried out using the semiempirical method of intermedia te neglect of differential overlap and atom-atom potentials, as implemented in the CASCADE code. The activation energies for three different hole-hopping mechanisms are calculated. It is shown that the 60° reorientations of a self-trapped hole and hopping to the nearest O-atom triangle reauire almost the same activation energy, approximately 0.9 eV, which agrees auite well with the experi-mental value for hole migration of 0.7 eV. A new mechanism of small-polaron motion is suggested.