[Pw_forum] from electrons : error # 1 charge is wrong

[Lorenzo Paulatto]

In data 24 settembre 2009 alle ore 12:03:02, dev sharma  
<decboy9 at gmail.com> ha scritto:

> Dear Sir,
>  what i was find in my output file  ,  is that  the structure is   
> metallic and asking for smearing and nosym see output below. I am doing   
> calculation on ZnO doped with N, with one Zn replaced by N. Sir any  
> comment or
> suggestion on this as ZnO is a insulator with band gap 3.32 eV approx.  
> And when i am giving the smearing and set nosym=.true., the error is  
> removed and positions are being releaxed.

I'm not sure I've understood your problem correctly, but in general, if  
you replace an atom with another there is no guarantee that the resulting  
crystal will still be insulator!

In particular, by replacing a Zn (12 electrons in valence) with a Nitrogen  
(5 electrons in valence) you will change the parity of the total number of  
electrons in the cell: if before you had an even number of electrons than  
it will become odd, i.e. if before you had an insulator than you will have  
a conductor. Keep in mind that you're not just replacing *one* atom,  
you're replacing one atom *per unit cell*.

best regards

P.S. I'm confused... are you Neel Sing?


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Lorenzo Paulatto
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