Figure 1. Vacancy formation energy ΔH in BaTiO3 as a function of the chemical potential μe of the electron reservoir.
The left column is under oxygen-poor condition with μO = −4 eV, and the right column is under oxygen-rich condition with μO = 0 eV. In each column, three different vacancy species are considered, namely
,
, and
. The number labelled near each line is the charge state q.
