[Pw_forum] impurity

[Stefano Baroni]

On Aug 16, 2008, at 6:45 AM, Mansoureh Pashangpour wrote:

> Dear all
> I am going to calculate affect of adding impurities to a system.I  
> know I must consider a supercell for this propose but I don't know  
> how and where I should add an impurity?

how could WE know, if you don't? it depends on stability issues (you  
may want to look for the minimum-energy geometry), if you think that  
the system you are interested in has had enough time to relax to the  
most stable configuration, or on the details of the preparation  
process, if you suspect that the system is trapped in one metastable  
confiuration

> How can I have different percent of impurities in a system?

how about considering different supercells with a different numbers of  
"stranger" atoms?

> please let me know its answer.
> good luck

all the same to you

> Mansoureh

how about your affiliation?

Cheers - SB

---
Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center -  
Trieste
http://www.sissa.it/~baroni / [+39] 040 3787 406 (tel) -528 (fax) /  
stefanobaroni (skype)

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