Fig. 2. Electronic structure of anatase/TiO2-II/rutile three-phase junction. (a) The band gap for rutile/TiO2-II and anatase/TiO2-II biphase crystals as calculated by HSE06 (left y-axis, solid lines) and PBE (right y-axis, dotted lines) functionals. Red: rutile; blue: anatase. (b, c) The band structures for the biphase crystals 12A/2II and 4R/1II. (d–g) The 3D isosurface contour plots of the VBM and CBM using the HSE06 functional for 12A/2II and 4R/1II biphase crystals. White: Ti atoms; red: O, the isosurface value is set as ±0.14 e Å–3.
