Environment-dependent interfacial strength using first principles thermodynamics: The example of the Pt-HfO₂ interface

A parameter-free, quantitative, first-principles methodology to determine the environment-dependent interfacial strength of metal-metal oxide interfaces is presented. This approach uses the notion of the weakest link to identify the most likely cleavage plane, and first principles thermodynamics to calculate the average work of separation as a function of the environment (in this case, temperature and oxygen pressure). The method is applied to the case of the Pt-HfO₂ interface, and it is shown that the computed environment-dependent work of separation is in quantitative agreement with available experimental data.