[Wien] Kpoint unit in the wien2k band structure

[Gavin Abo]

Yes, the k numbers in case.spaghetti_ene should always be in 2*pi/bohr.

As was stated in [1], if Ang numbers are inputted (into StructGen of 
w2web), it is converted from Ang to bohr and stored always as a bohr 
number in case.struct and an Ang flag is set (if that unit type was 
selected in StructGen) in the file.  The Ang flag in case.struct is for 
StructGen, if the program sees the flag, then StructGen converts the 
bohr number before StructGen displays it to you.

The energy numbers in case.spaghetti_ene, however, might not always be 
in eV.  If you look at page 194 in section "8.23.2 Input" of the WIEN2k 
19.1 usersguide [2], there is "energy switch (1:Ry, 2:eV)" in 
case.insp.  So the energy might be in unit of Ry in case.spaghetti_ene 
if that switch was set to 1.

[1] 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg05273.html
[2] http://susi.theochem.tuwien.ac.at/reg_user/textbooks/usersguide.pdf

On 12/25/2019 12:06 AM, Aamir Shafique wrote:
> Dear Govin and Oleg,
> Thank for your reply. The k path will be still in 2pi/bohr if I used 
> ang (for lattice parameter) as an input.
>
> *With Best Regards, *
>
> *Aamir Shafique
> *
>
>
>
> On Tue, Dec 24, 2019 at 8:37 PM Oleg Rubel <rubelo at mcmaster.ca 
> <mailto:rubelo at mcmaster.ca>> wrote:
>
>     I would recommend using the file 'case.spaghetti_ene'. It looks
>     like this
>
>     [rubel at gra-login1 case]$ head case.spaghetti_ene
>        bandindex:           1
>        -0.03869   0.00000   0.00000   0.00000 -35.66092
>        -0.03095   0.00000   0.00000   0.00774 -35.66093
>        -0.02321   0.00000   0.00000   0.01548 -35.66094
>        -0.01934   0.00000   0.00000   0.01935 -35.66094
>        -0.01548   0.00000   0.00000   0.02321 -35.66094
>        -0.01161   0.00000   0.00000   0.02708 -35.66095
>        -0.00967   0.00000   0.00000   0.02902 -35.66095
>        -0.00774   0.00000   0.00000   0.03095 -35.66095
>        -0.00580   0.00000   0.00000   0.03289 -35.66095
>     ...
>
>     The column 4 is k along the path (units 2pi/bohr). The 5th column
>     is the
>     energy (eV) relative to the Fermi energy.
>
>     For fitting, follow Gavin's instructions (see recent posts). In
>     addition
>     to that, I suggest fitting data only within 30-40 meV from the band
>     extremum, which is roughly kT at the room temperature. Higher
>     energies
>     will not be slumped by charge carriers and thus are irrelevant. Some
>     bands can be quite non-parabolic. It is always good to have at
>     least 7
>     point for fitting and check if the 2nd order coefficient in the
>     polynomial changes if you increase the polynomial order to 4th order.
>
>     Good luck
>     Oleg
>
>     -- 
>     Oleg Rubel (PhD, PEng)
>     Department of Materials Science and Engineering
>     McMaster University
>     JHE 359, 1280 Main Street West, Hamilton, Ontario L8S 4L8, Canada
>     Email: rubelo at mcmaster.ca <mailto:rubelo at mcmaster.ca>
>     Tel: +1-905-525-9140, ext. 24094
>     Web: http://olegrubel.mcmaster.ca
>
>     -- 
>     Oleg Rubel (PhD, PEng)
>     Department of Materials Science and Engineering
>     McMaster University
>     JHE 359, 1280 Main Street West, Hamilton, Ontario L8S 4L8, Canada
>     Email: rubelo at mcmaster.ca <mailto:rubelo at mcmaster.ca>
>     Tel: +1-905-525-9140, ext. 24094
>     Web: http://olegrubel.mcmaster.ca
>
>     On 2019-Dec.-24 02:58, Aamir Shafique wrote:
>     > Hello,
>     > Hope you are well. I want to calculate the effective mass at high
>     > symmetry point but I am unable to find the Kpoint unit in band
>     structure
>     > whether it is 1/bohr or 1/ang.
>     >
>     > *With Best Regards, *
>     >
>     > *Aamir Shafique
>     > *
>     >
>     > *-----------------------------------------------------------------*
>     > *Postdoctoral fellow*
>     >
>     > *Physical Sciences and Engineering*
>     >
>     > *+****King Abdullah University of Science and Technology *
>     >
>     > Thuwal 23955, Saudia Arabia.
>     >
>     > (*Direct*- +966  54  5351602
>     >
>     > **Email* – aamir.shafique at kaust.edu.sa
>     <mailto:aamir.shafique at kaust.edu.sa> <mailto:ukkayani at hec.gov.pk
>     <mailto:ukkayani at hec.gov.pk>>
>     >
>
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