Empirical Calculations of the Formation Energies of Intrinsic Defects in   Lithium Niobate
  Results of our shell-model calculations concerning the determination of empirical parameters of inter-ionic potentials and the formation energies of point defects in LiNbO3 are presented. We employed the relaxed fitting method which is particularly appropriate for the modeling of low-symmetry structure. Attention is paid to guarantee the simulation precision of the parameters who are sensitive for defect formation energy calculations. It is shown that Li Frenkel disorders are the main intrinsic defects in stoichiometric lithium niobate and Li vacancy model is the dominant defect species in congruent lithium niobate. 
Shaoxin Feng, Qinghua Jin, Baohui Li, Zhenya Guo, Datong Ding