Strong polaronic effects on rutile TiO2 electronic band edges -: art. no. 231912

Thin TiO2 films are prepared by dc magnetron sputtering as well as by the sol-gel technique, and the optical band edge absorption alpha(omega) is obtained from transmission spectroscopy. The electronic structure and optical properties are studied employing a first-principle linearized augmented plane-wave method within the local density approximation (LDA), improved by an on-site Coulomb self-interaction potential (LDA+U-SIC). We show that the correction potential, the polaronic screening, and the spin-orbit interaction are crucial for determining the TiO2 effective electron and hole masses. The dielectric function and the high-frequency constant epsilon(0 <<omega << E-g/h) show pronounced anisotropy. The electron-optical phonon interaction affects epsilon(omega approximate to 0) strongly. (c) 2005 American Institute of Physics.