ArticleAuthors: Nguyen, Hoang Linh; Nguyen, Hoang Tuan; Dang, Duc Dung; Phung, Quoc Bao; Bach, Thanh Cong; Le, Thi Hai Thanh (2019)
In this study, we have performed density functional theory based calculations to investigate the effect of
alkali substituents M on the structure and electronic properties of (Bi0.5M0.5)TiO3 compounds with
M ¼ Li, Na and K. When the ionic radius of the substituting M cation increases, the corresponding direct
band gap of (Bi0.5M0.5)TiO3 also increases. The same trend is found for the O-deficient Bi0.5M0.5TiO3-
d compounds, which were investigated by removing one Oxygen atom from the super cell creating an Ovacancy
in it. The presence of the O-vacancy breaks the local symmetry of the crystal structures and
generates excess electrons in the O-deficient compounds. This results in t... 
