The formation and migration of defects relevant to the Li ionic conduction in Li3N

were investigated using first-principles calculations. For undoped Li3N, Frenkel

reactions generating the Li vacancy and two types of Li interstitial were found to

dominate the defect equilibria. In the layered structure of Li3N, the Li vacancy

migrates selectively toward the intralayer direction, whereas the Li interstitial

readily moves in both intralayer and interlayer directions. Despite the significant

crystallographic anisotropy and the orientation dependence of dominant charge

carriers, the resultant activation energy for the Li ionic conduction was nearly

isotropic in the undoped system. The presence of H impurities yields Li vacancyrich

defect equilibria, leading to an anisotropic ionic conduction governed by the Li vacancy. These findings elucidate the variable anisotropy in the ionic conductivity

of Li3N.

Variable Anisotropy of Ionic Conduction in Lithium Nitride: Effect of Duplex-

Charge Transfer. I.Kishida, F.Oba, Y.Koyama, A.Kuwabara, I.Tanaka: Physical

Review B, 2009, 80[2], 024116