Hydrogen-induced metallicity of SrTiO3 (001) surfaces: A density functional theory study

The effect of atomic hydrogen adsorption on TiO2-terminated and SrO-terminated SrTiO3 (001) surfaces is studied using density functional theory calculations. Several adsorption coverages (1/12, 1/6, 1/3, 1/2, 2/3, and 1 monolayer) are considered. It is found that the hydrogen adsorption shows site selectivity and causes remarkable surface distortion. Surface metallicity induced by the hydrogen adsorption is observed and revealed to be caused by the electron donation from hydrogen to the surface. Our results suggest a mechanism of hydrogen-induced degradation and hydrogen-sensitive I-V characteristics of SrTiO3-based devices.