Structure, Composition, and Electronic Properties of TiOx/Mo(112) Thin Films

Titanium oxide films of various composition grown on a Mo(112) metal substrate have been investigated with the help of first principles density functional theory plane wave calculations using the PW91 functional. We show that at the experimental pressure and temperature conditions used to grow the films a structure with composition TiO 3 is preferred. This conclusion is based on the thermodynamic analysis of the film stability as a function of the oxygen partial pressure and is corroborated by the comparison of computed and measured properties like scanning tunneling microscopy images, vibrational modes, and core level binding energies. The electronic properties of the films are discussed in terms of density of states, charge-transfer at metal/oxide interfaces, and work function changes.