Using first-principles electronic-structure calculations of static potential energy surfaces, we investigate the atomic-scale energetic barriers encountered during sliding at $\mathrm{Mo}{\mathrm{S}}_2$ (001) and $\mathrm{Mo}{\mathrm{O}}_3$ (001) surfaces and at the $\mathrm{Mo}{\mathrm{S}}_2∕\mathrm{Mo}{\mathrm{O}}_3$ interface. The results indicate the minimum energy path to sliding and provide an upper bound to the force that must be applied in order to initiate sliding. The results further suggest that the lowest energy pathway is to slide $\mathrm{Mo}{\mathrm{O}}_3$ over $\mathrm{Mo}{\mathrm{S}}_2$ along the channel direction formed by S atoms at the sliding interface, and the highest energy pathway involves $\mathrm{Mo}{\mathrm{O}}_3$ (001) interlayer sliding, which is consistent with the results of experimental microscopic investigations of similar crystalline interfaces.

• Received 1 October 2007

DOI:https://doi.org/10.1103/PhysRevB.77.104105