[Wien] pdos for restricted k-range or in restricted space

[Peter Blaha]

I've made some small modifications of SRC_tetra, such that it can 
calculate the DOS only for tetrahedra which contain the desired k-point.

a) Check case.klist and select the k-point of your choice (eg. Gamma as 
number 1, or XX for any other selection.

b) modify case.int as: (3rd line)
PbTiO3             #Title
-0.91780 0.002 .9915901704 0.003    #Emin, DE, Emax, Gauss-Broad
   11   N   0.000      KSEL=1        #Number of DOS-cases,G/L/B 
broadening (Ry), KSELect=XX

Using the keyword KSEL= directs tetra to integrate only those tetrahedra 
which contain the selected k-point.
A negative number (-XX) (or no KSEL=) switches this off and the regular 
integration happens.

Depending on the density of your -mesh, it will cover a certain volume 
of the BZ (a few percent ...).

NOTE: At the moment you cannot add this up for 2 different k-points, 
since X1 and X2 may share the same tetrahedron and thus double counting 
occurs. It would be straight forward, however, to specify several 
k-points at the same time and use all tetrahedra which contain at least 
one of the selected k-points ....


On 8/28/19 8:59 AM, Peter Blaha wrote:
> Not with standard wien2k tools.
> 
> However, you can write your own little programs, eg.
> 
> reading the case.qtl file for an arbitrary k-mesh of your choice and do 
> a "root sampling", i.e. divide your energy mesh into some intervals and 
> count the number of eigenvalues (times the multiplicity of the k-point) 
> in each E-interval. Plot the corresponding histogram.
> 
> An alternative is to modify tetra such, that instead of summing over all 
> tetrahedra, it sums only over those involving k-points of your choice. 
> For this you need to understand the case.kgen file, which lists the 
> vertices of all tetrahedra and you select only thos which contain the 
> desired k-points.
> 
> 
> 
> On 8/27/19 6:12 PM, Jens Biegert wrote:
>> Dear All,
>>
>> I was wondering wether I can get the DOS, or better PDOS, for a 
>> specified k-path. Say, instead of an integration over the whole 
>> Brillouin zone, just (like for the bandstructure) along gamma to K to 
>> M to gamma.
>>
>> If not possible, can I restrict 3D k-space integration close to e.g. 
>> the K point such as to get the PDOS close to K?
>>
>> I saw some previous answers that seem to hint at this not being 
>> possible, but it was not clear to me.
>>
>> Best regards,
>>
>> Jens Biegert
>>
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> 

-- 

                                       P.Blaha
--------------------------------------------------------------------------
Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
Email: blaha at theochem.tuwien.ac.at    WIEN2k: http://www.wien2k.at
WWW:   http://www.imc.tuwien.ac.at/TC_Blaha
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