[Wien] generalized regular k-point grids

[Peter Blaha]

Hi,

Yes, WIEN2k is ready to accept any k-grid when using smearing methods, 
however, you need to supply the proper weights.

I do not know what symmetry your cell has, but I can see only weights of 
1, 2 and 4 ? Is this correct ?
It means you have only 4 symmetry operations for this cell ??

PS: Have you tried TEMP instead of TEMPS ? As far as I understand, TEMP 
corrects towards zero Kelvin and should be compatible with TETRA. And of 
course with a very small smearing parameter, TEMPS should go towards 
TEMP --> TETRA (if the k-mesh is good enough).

PPS: Be aware of different coordinate systems for different lattices !
VASP and WIEN2k may eventually ?? specify the coordinates in different 
coordinates (cartesian vs. fractions of (non-orthogonal) rec. lattice 
vectors.

Peter Blaha

Am 10/14/21 um 2:52 PM schrieb Pavel Ondračka:
> Dear Wien2k mailing list,
> 
> Is Wien2k ready for a general k-point grid or is some part of the code
> assuming regular grid?
> 
> I was reading some papers about how the generalized regular k-point
> grids have better efficiency over the standard Monkhorst-Pack ones...
> For example this paper has also an implementation
> https://msg.byu.edu/docs/papers/autoGR.pdf
> 
> It generates a k-point list in VASP KPOINTS format:
>   0.000000000000  0.000000000000  0.000000000000     1
> -0.166666666667  0.166666666667  0.000000000000     2
> -0.333333333333  0.333333333333  0.000000000000     2
>   0.500000000000 -0.500000000000  0.000000000000     1
>   0.062500000000 -0.020833333333  0.035714285714     4
> -0.104166666667  0.145833333333  0.035714285714     4
> -0.270833333333  0.312500000000  0.035714285714     4
> .....
> 
> I just do the stupid thing and convert it to the .klist format by
> multiplying with 1e9 and applying the proper formating, i.e.:
>           1         0         0         01000000000  1.0
>           2-166666666 166666666         01000000000  2.0
>           3-333333333 333333333         01000000000  2.0
>           4 500000000-500000000         01000000000  1.0
>           5  62500000 -20833333  357142851000000000  4.0
>           6-104166666 145833333  357142851000000000  4.0
>           7-270833333 312500000  357142851000000000  4.0
> .....
> 
> Now everything seems to run OK at the first glance (lapw2 crashes with
> TETRA ofc but TEMPS seems to be OK) but the energies are not so close
> (I would expect that at very large number of k-points it should give
> the same results as standard Wien2k MP grid), but there is a difference
> of maybe 2mRy/atom. So I guess there is still something somewhere
> missing for this to work?
> 
> Best regards
> Pavel
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-- 
Peter Blaha, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300          Email: peter.blaha at tuwien.ac.at
WWW: http://www.imc.tuwien.ac      WIEN2k: http://www.wien2k.at