Re: [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 > wrote:


I would recommend using the file 'case.spaghetti_ene'. It looks
like this

[rubel@gra-login1 case]$ head case.spaghetti_ene
   bandindex:           1
   -0.03869   0.0   0.0   0.0 -35.66092
   -0.03095   0.0   0.0   0.00774 -35.66093
   -0.02321   0.0   0.0   0.01548 -35.66094
   -0.01934   0.0   0.0   0.01935 -35.66094
   -0.01548   0.0   0.0   0.02321 -35.66094
   -0.01161   0.0   0.0   0.02708 -35.66095
   -0.00967   0.0   0.0   0.02902 -35.66095
   -0.00774   0.0   0.0   0.03095 -35.66095
   -0.00580   0.0   0.0   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: rub...@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: rub...@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.shafi...@kaust.edu.sa
 >
>

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Re: [Wien] Kpoint unit in the wien2k band structure

[Aamir Shafique]

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  wrote:

> I would recommend using the file 'case.spaghetti_ene'. It looks like this
>
> [rubel@gra-login1 case]$ head case.spaghetti_ene
>bandindex:   1
>-0.03869   0.0   0.0   0.0 -35.66092
>-0.03095   0.0   0.0   0.00774 -35.66093
>-0.02321   0.0   0.0   0.01548 -35.66094
>-0.01934   0.0   0.0   0.01935 -35.66094
>-0.01548   0.0   0.0   0.02321 -35.66094
>-0.01161   0.0   0.0   0.02708 -35.66095
>-0.00967   0.0   0.0   0.02902 -35.66095
>-0.00774   0.0   0.0   0.03095 -35.66095
>-0.00580   0.0   0.0   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: rub...@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: rub...@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.shafi...@kaust.edu.sa 
> >
> >
> > ___
> > Wien mailing list
> > Wien@zeus.theochem.tuwien.ac.at
> > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> > SEARCH the MAILING-LIST at:
> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
> >
> ___
> Wien mailing list
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Re: [Wien] Kpoint unit in the wien2k band structure

[Oleg Rubel]

I would recommend using the file 'case.spaghetti_ene'. It looks like this

[rubel@gra-login1 case]$ head case.spaghetti_ene
  bandindex:   1
  -0.03869   0.0   0.0   0.0 -35.66092
  -0.03095   0.0   0.0   0.00774 -35.66093
  -0.02321   0.0   0.0   0.01548 -35.66094
  -0.01934   0.0   0.0   0.01935 -35.66094
  -0.01548   0.0   0.0   0.02321 -35.66094
  -0.01161   0.0   0.0   0.02708 -35.66095
  -0.00967   0.0   0.0   0.02902 -35.66095
  -0.00774   0.0   0.0   0.03095 -35.66095
  -0.00580   0.0   0.0   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: rub...@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: rub...@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.shafi...@kaust.edu.sa 


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Re: [Wien] Kpoint unit in the wien2k band structure

[Gavin Abo]

The WIEN2k 19.1 usersguide [1] (page 11) states that a type of natural 
units [2] is used: "Rydberg atomic units are used except internally in 
the atomic-like programs (LSTART and LCORE) or in subroutine outwin 
(LAPW1, LAPW2), where Hartree units are used. The output is always given 
in Rydberg units."


The unit of k in case.spaghetti_ene is given in the post at:

https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg05273.html

There k is 2*pi//a/, where /a/ is in unit of bohr. Thus, the answer to 
your question is 1/bohr.


Of course, if you are using the parabolic effective mass approximation, 
converting it to the SI system with unit of pi/m is recommended [3] but 
that approximation typical works best in simplistic cases [4].  As far 
as I know, the finite difference method that most likely would work 
better as a general approach for all structures has still not been 
implement yet for WIEN2k [5].


[1] http://susi.theochem.tuwien.ac.at/reg_user/textbooks/usersguide.pdf
[2] https://en.wikipedia.org/wiki/Natural_units#Atomic_units
[3] 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg16786.html
[4] 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg19411.html
[5] 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg11446.html


On 12/24/2019 12:58 AM, 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.shafi...@kaust.edu.sa 
___
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[Wien] Kpoint unit in the wien2k band structure

[Aamir Shafique]

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.shafi...@kaust.edu.sa 
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