title: First-principles study of diffusion of Li, Na, K and Ag in ZnO.
abstract: Based on ab initio total energy calculations, Li, Na and Ag interstitials are found to be stable with at least a 1.56 eV energy barrier to transform to a zinc substitutional site in ZnO, whereas K interstitial has a relatively small energy barrier at 0.79 eV. The isolated dopant substitutional defects (Li(Zn), Na(Zn), K(Zn) and Ag(Zn)) are found to be rather stable, with at least a 3.4 eV energy barrier to transform to an interstitial site. All of the dopant interstitials (Li(i), Na(i), K(i) and Ag(i)) are fast diffusers. The diffusion of Li interstitial is isotropic, whereas the diffusion of Na, K and Ag interstitials is highly anisotropic. Fundamental processes of the vacancy-assisted mechanisms are systematically investigated and specific values of the energy barriers are obtained.
authors.affiliation: Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China.
authors.forename: Gui-Yang
authors.initials: GY
authors.lastname: Huang
authors.forename: Chong-Yu
authors.initials: CY
authors.lastname: Wang
authors.forename: Jian-Tao
authors.initials: JT
authors.lastname: Wang