Hi everyone,
I’m trying to calculate the surface energy of the TiO₂-terminated (001) surface of tetragonal BaTiO₃ using VASP. Since the slab doesn’t contain an integer number of BaTiO₃ unit cells, I understand I need to use chemical potentials.
I’ve already run six calculations:
I know the general surface energy formula involves chemical potentials of Ba, Ti, and O, but I’m not sure how to derive those from my runs.
How can I extract the chemical potentials from these results?
Thanks in advance!
Hey Kimia Lotfian
Nonstoichiometric surfaces take a bit more work because you can't rely just on total energies as we normally do for stoichiometric ones, like you said. You need to apply the right thermodynamic constraints to make sure the system stays stable, meaning no unwanted phases like Ba or Ti form, etc. Once that's done, you can plug everything into the surface energy formula. So, I have done the trivial case only - stoichiometric surface - and sorting out those constraints will likely take some time, but skimming through this paper, it seems that they did what you need.
Article Stoichiometric and Nonstoichiometric Surface Structures of P...
Best,
Gabriel Vinicius
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