Optical properties of anatase and rutile TiO2 studied by GGA+U
Li Jinping1, 3, †, Meng Songhe1, Qin Liyuan1, Lu Hantao2
       

(color online) (a) The DOS of r-TiO with 6.25% vacancy by GGA and GGA+U; (b) the DOS of the pure r-TiO and r-TiO with 12.5% Hf doped by GGA+U.