Understanding electronic and optical properties of La and Mn co-doped anatase TiO2

The electronic structures, dipole moment, and optical properties of La-doped, Mn-doped, and La-Mn-doped anatase TiO2 have been investigated by means of GGA + U first-principles method, showing that the absorption coefficients of the La-Mn-doped TiO2 under visible light to be sensitive to the doping positions of La and Mn atoms. La-Mn-TiO2(1) exhibits the largest absorption coefficient in visible light because of the smallest band gap. Additionally, for the La and Mn co-doped TiO2, the large dipole moment of TiO6 octahedron is in prejudice of enhancing the optical responses under the visible light. We successfully probe the interesting optical response mechanism in this work.