Epitaxial molybdenum oxide grown on MO (110): LEED, STM, and density functional theory calculations

Abstract

The oxidation of Mo(110) was studied at 1000 ?C and 1?10?6 Torr oxygen. Low energy electron diffraction and scanning tunneling microscopy data were used to give a detailed analysis of the oxide surface structure. From this data a model was built, and through the use of density functional theory (DFT) calculations, we show that a strained bulklike MoO2(010) ?surface oxide? is in excellent agreement with the experimental data. The stability of this oxide was accounted for by a strong adhesion at the interface. The origin of this strong adhesion between the film and substrate can be related to the charge redistribution at the interface, which is analogous to the macroscopic image charge interaction between the two. Furthermore, we employed DFT calculations to illustrate the charge redistribution at the interface and estimate the work of adhesion for this system. The calculated work of adhesion is around 7 J?m2, indicating that there is indeed a strong interaction between the film and substrate as expected.