Hi, Fedwa,
I suggest you try the first choice, i.e. put Ga in the interestital and
add a Netcharge in the system.
If the Ga-2 is stable, the netcharge may distribute
around this Ga atom
(you should plot these charge density to look at the distribution.)
Anyway, it should be detemined by the self-consistent
electronic structure.
Good Luck!
Fedwa El-Mellouhi wrote:
Dear colleagues,
We already used siesta to treat vacancies in GaAs in various charge
states. For vacancies the additional charge added to the system
(NetCharge = -1, -2 ....) is located at the vacant site, so this is
physically correct.
Now that we want to study interstitial, the picture is not clear for me:
I'm thinking of two possibilities :
1- Add one Ga atom at the interstitial position, next add a Netcharge
to the system for example -2.
In case the charge is not localized near the interstitial, for
example highly delocalized and spreads over the whole crystal ; is it
physically correct to assume that it is equivalent Ga-2 ion .
2- Or, insert a Ga-2 ion rather that putting NetCharge =-2 but I'm not
sure if this is feasible with siesta.
Can some body give some advice please.
Thanks in advance
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