[Wien] help required

[Rocquefelte]

I have difficulties to follow your arguments. In your first email you 
have mentioned that you did non spin polarized calculations, and now you 
are speaking about ferromagnetic character at M point!

In addition, I do not understand the following line: "DOS and band 
structre showing totally opposite behaviour".

My feeling remains the same and particularly in the present case. You 
are looking at graphene, a 2D system for which the band dispersion is 
large.
You must see Van't Hoff singularities in the DOS and you need to have a 
dense k-mesh to have a well-converged DOS.
Did you check the convergency of your DOS calculation but using denser 
k-meshes?

Regards

Xavier




On 04/07/2012 12:45 PM, arqum hashmi wrote:
> Thanks Sir Xavier,
> but the problem is this that both DOS and band structre showing 
> totally opposite behaviour.
> my system is graphene with some doping of Boron nitride.
> DOS is good as we expect but band structure shows really strange 
> behaviour. graphene  has zero bandgap in brillioun zone at K point and 
> when i used graphene with BN, we obtain some ferromagnetic at M point 
> when we plot band structure.
> i don't know whats wrong with band structure.
> Best Regrads
> Arqum Hashmi
>
> *From:* Rocquefelte <Xavier.Rocquefelte at cnrs-imn.fr>
> *To:* A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at>
> *Sent:* Saturday, April 7, 2012 7:02 PM
> *Subject:* Re: [Wien] help required
>
> The band gap estimated from the DOS is always larger than the one 
> extracted from the band structure (which is more accurate).
> To estimate the fundamental band gap you should consider the one 
> deduced from the band structure.
>
> The difference you observed is certainly due to the existence of a 
> broad band which has a very low density near the Fermi energy. As a 
> consequence, you can have the feeling that you have a gap by looking 
> at the DOS.
>
> Could you give more details about your calculations ? Which system ? 
> The value of the band gap from the DOS ?
>
> Regards
>
> Xavier
>
>
> On 04/07/2012 07:41 AM, arqum hashmi wrote:
>> Dear Wien2k Users
>>
>> I am doing non spin polarized calculation. In this calculation, DOS 
>> and Band structure are not consistent with each other. DOS shows that 
>> it has some band gap but in band structure it shows that it is 
>> metallic. I don't know what is the problem in this and why DOS and 
>> Band structure is inconsistent with each other.
>> i expect that DOS is correct but something is wrong with band structure.
>> If any one of you give any suggestion that how i can solve this 
>> problem. I will be very thankful to you.
>>
>> Best Regards
>> Arqum Hashmi
>>
>>
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>
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