[Wien] Formation energy of a deffective lattice

[Muhammad Huda]

Hi Stefaan,

There are several references where formation energy
definitions are explained in details, and also how to
calculate them with first principle theories:

1. S.-H. Wei, Computaional Mat. Sci., vol. 30, pp 337,
2004.
2. S. B. Zhang, J. Phys.:Condens. Matter, vol. 14, pp
R881, 2002.
3. C. G. Van de Walle and J. Neugedauer, J. App. Phys.
vol. 95, pp 3851, 2004.

It should be clear from the above papers that atomic
and electronic chemical potentials are needed to
correctly evaluate the formation energies. Otherwise
one cannot compare formation energy of one type of
defect with others. Thanks,

Muhammad Huda

--- Stefaan Cottenier
<Stefaan.Cottenier at fys.kuleuven.be> wrote:

> 
> This reminds me to a related issue on which I never
> found a satisfying 
> answer. Perhaps someone has ideas or references? The
> equation given by 
> Ricardo Faccio applies to a defect that is created
> by a previously 
> isolated atom that gets incorporated into the bulk
> and stays there. But 
> what if you want to *compare* the formation energy
> of such a case with 
> the formation energy of a case where the previously
> isolated atom 
> *replaces* a bulk atom? The best I can think about
> is to add a dummy 
> isolated bulk atom in the equation, to have the same
> number of atoms at 
> either side of the minus sign:
> 
> E(defect_formation)=[E(defective)+E(isolated bulk
> atom)] - 
> [E(bulk)+E(isolated_impurity_atom)]
> 
> But I'm not sure this is really correct. For
> instance, can this be 
> related in some way to the chemical potential? I bet
> many people have 
> thought about this before. If anyone has recipes or
> references, I'm 
> interested to hear them.
> 
> Stefaan
> 
> 
> 


 
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