Troubles with orient/fcc

Hi all

I am trying to study the mobility of a Sigma5 (001) GB in a model Y2O3-ZrO2 bicrystal using the “orient/fcc” fix. In this systems, the cation sublattice is a fcc one, so I am applying the fix only to cations. However, I have found a few troubles. Before going on, I would like to know if my approach is valid, that is, if “fix orient/fcc” can be applied to one sublattice in a binary system like YSZ. Any help?

Thanks in advance

Cheers

Juanjo

Juan J. Meléndez
Associate Professor
Department of Physics · University of Extremadura
Avda. de Elvas, s/n 06006 Badajoz (Spain)
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I don't know. The question would be what happens to the other
atoms and whether they respond appropriately to the force
on the other cations that surround them.

I don't know of anyone who has tried to do what you
are suggesting.

Steve

Hi Juanjo,

I have studied this command for a while, according to my understanding, it is hard to be applied to your simulation.
Firstly, it is hard to write the two orientation files(i.e. xi.vec, chi.vec) for your model.

Secondly, as i understand,this command is used to simulate gb mobility of pure material. For model with several kinds of atoms, this command cann't get the synthetic orientation-dependent driving force for a specific kind of atom, e.g. the cation in your model.

Thirdly, if you want to get mobility, the model must be heated to a certain temperature, otherwise the gb will keep inmobile. Heating, especially heating to a high temperature, will cause huge fluctuations of all atoms, while fluctuations of atoms away from gb will also cause these atoms suffer the synthetic dirving force, so you need to make some modification to this command.

All i wrote above are from my study of this command, some opinions may not be quite right. Hope it wil help you.

L.Yang

Thirdly, if you want to get mobility, the model must be heated to a certain temperature, otherwise the gb will keep inmobile. >Heating, especially heating to a high temperature, will cause huge fluctuations of all atoms, while fluctuations of atoms away from >gb will also cause these atoms suffer the synthetic dirving force, so you need to make some modification to this command.

I agree with all the comments except this one. The point of fix
orient/fcc is to be able to induce
mobility w/out having to go to very high temperatures, i.e. to see the
GB move relatively
quickly in a simulation due to the driving force, and not due to
imposing high temperatures.

That said, using it for the hybrid system you wish (instead of pure
fcc) may take some modification
to the code.

Steve