Confinement effects for the F center in non-stoichiometric BaZrO3 ultrathin films

First principles calculations of the atomic, electronic structure, and phonons frequencies were performed to investigate confinement effects on the oxygen vacancy (the F color center) in BaZrO₃ ultrathin films. The defect was considered both inside the films and on the (001) surface with BaO and ZrO₂ terminations. We consider the effects of the one-dimensional confinement through varying the number of planes in the films from 3 to 9 and comparing the results with those obtained for the bulk material. We have studied how the one-dimensional confinement affects the electronic properties (band structure, Mulliken atomic charges) and the phonon frequencies of the defective systems, and thus how the defect formation energy in thin films at finite temperatures is affected as compared with the bulk material.