Ionic conduction mechanism in Ca-doped lanthanum oxychloride.

The mechanism of ionic conduction in Ca-doped lanthanum oxychloride (LaOCl) was investigated using first-principles calculations based on density functional theory. The calculations of the point defect formation energies suggest that Cl ion vacancies and substituted Ca ions at La sites were dominant point defects. Although the migration energy of an O ion is 0.95 eV, the migration energy of a Cl ion was calculated to be 0.44 eV, which is consistent with the reported experimental value. These results imply that the main carrier in Ca-doped LaOCl is Cl ions and ionic conduction occurs by a Cl ion vacancy mechanism.