[Wien] help required

[Rocquefelte]

For the convergency of the DOS you simply have to plot the DOS for 
different k-meshes (increasing progressively the number of k-points) and 
when the DOS stops to evolve then you are converged.

Regards

Xavier


On 04/07/2012 03:29 PM, arqum hashmi wrote:
> Thanks a lot sir Xavier,
> Before this i also thinked about this that  i don't have denser k mesh 
> thats why i didn't get correct results.
> yeah thats why i am saying to you that band structure giving very 
> unnatural behaviour.  Sorry not ferromagnetic you can say that 
> conductor behaviour because band lines crossing fermi level.
> opposite behaviour means DOS showing bandgap but band structure 
> showing conducting behaviour.
> how can i check the convergency of my DOS calculation.
> i am really worried about this.
> Best Regards
> 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 8:48 PM
> *Subject:* Re: [Wien] help required
>
> 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> 
>> <mailto:Xavier.Rocquefelte at cnrs-imn.fr>
>> *To:* A Mailing list for WIEN2k users 
>> <wien at zeus.theochem.tuwien.ac.at> 
>> <mailto: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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