How to create the random defects


I want to simulate the ionic oxide ReTa3O9 (Re is the rare earth element) that contains 1/3 Re3+ vacancies to maintain the electric neutrality. Those Re3+ vacancies are randomly distributed in the lattice. So I would like to know how to create such random distribution of Re3+ defects in the desired proportion.

Thanks very much.

I’m afraid that’s a question that goes to the design of your research project & so more for your supervisor as it’s not related to GULP. As a pointer, you need to look up the supercell and mean field approaches to disorder in the literature.

We need to create a supercell where 1/3 Re atoms need to be randomly deleted to form vacancies. To my knowledge, this can be done with commands in LAMMPS. So, I wonder if it can also be done in GULP, i.e. randomly deleting the Re atoms in the designed ratio (e.g. 30%).

GULP doesn’t have a random deletion command, but you would need an ensemble of different configurations to average over.

Thanks very much!
Best regards.