[Wien] Effective Mass

[Oleg Rubel]

Hi Pablo,

Regarding NBvalMAX: The manual says, "optional input. Setting this to the number of occupied bands (see case.output2) will reduce cpu-time of optics (for large cases, MM only between occupied and empty bands)." For the purpose of m*, I would definitely not try to set it to the number of valence bands, as the name might suggest. Your setting 9999 is conservative. The reader of the WIEN2k mommat file assumes that the data are presented as a triangular matrix p(i,j), with i=1,...,n_max and j=i,...,n_max. It will very likely fail if either index does not extend all the way to nmax.

This tutorial (https://github.com/rubel75/mstar/wiki/Tutorial-Si-with-SOC-(WIEN2k)) should help with extraction of m* from output data.

Best regards,
Oleg

> -----Original Message-----
> From: Wien <wien-bounces at zeus.theochem.tuwien.ac.at> On Behalf Of
> delamora
> Sent: Tuesday, July 28, 2026 8:09 PM
> To: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at>
> Subject: [Wien] RV: Effective Mass
> 
>   Caution: External email.
> Oleg,
> Thank for your quick reply
> I edited the
>  GaAs1.inop
> 
> 500 1       number of k-points, first k-point
> -5.0 5.0 9999 Emin, Emax for matrix elements, NBvalMAX
> 2             number of choices (columns in *outmat): 2: hex or tetrag. case
> 1             Re xx
> 3             Re zz
> ON            ON/OFF   writes MME to unit 4
> 
> and it worked, but what is "NBvalMAX"
> And where I see the "Effective Mass"
> 
> Saludos
> 
> Pablo
> ________________________________
> 
> De: Wien <wien-bounces at zeus.theochem.tuwien.ac.at> en nombre de Oleg
> Rubel <rubelo at mcmaster.ca>
> Enviado: martes, 28 de julio de 2026 04:40 p. m.
> Para: A Mailng list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at>
> Asunto: Re: [Wien] Effective Mass
> 
> Dear Pablo,
> 
> It seems that the error message points to the source of the problem 😉
> The file with momentum matrix elements ` GaAs1.mommat2up` is empty (0
> lines). I would check which files are created/modified as the result of ` x optic -
> so -up`.
> 
> Best regards,
> Oleg
> 
> > -----Original Message-----
> > From: Wien <wien-bounces at zeus.theochem.tuwien.ac.at> On Behalf Of
> > delamora
> > Sent: Tuesday, July 28, 2026 6:30 PM
> > To: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at>
> > Subject: [Wien] Effective Mass
> >
> >   Caution: External email.
> > Dear WIEN2k community,
> >
> > I am trying to calculate the "Effective Mass"
> > I am doing the example "GaAs" that is in the article;
> >
> > Perturbation approach to ab initio effective mass calculations
> > Computer Physics Communications 261 (2021) 107648
> >
> > In section "2.3. Sample work flow"
> >
> > After doing the GaAs.struct file I do the following instructions;
> > init_lapw -b -vxc
> > 13 -rkmax 7 -numk 500 run_lapw -ec 0.00001 -cc 0.0001 save_lapw -d
> > noSOC init_so_lapw run_lapw -ec 0.00001 -cc 0.0001 -so x lapw1 x
> > lapwso ln -sf GaAs1.vsp GaAs1.vspup ln -sf GaAs1.vsp GaAs1.vspdn ln -s
> > case.vectorso case.vectorsoup cp
> > /home/Programas/WIEN2k/SRC_templates/case.inop
> > GaAs1.inop x optic -so -up
> >
> > x mstar -up -settol 0.00001
> >
> >
> > *** Here I get an error;
> >  Detected input arguments = 2
> >  Input mommat file = ./GaAs1.mommat2up  Degeneracy tolerance dEtol =
> > 0.00001 [Ha]  Confirming text-to-number conversion dEtol =
> > 1.00000E-05 [Ha]  The input file ./GaAs1.mommat2up was found.
> >   number of lines in mommat file = 0
> >  The file ./GaAs1.mommat2up is too short and most likely useless.
> > Stopping 0.003u 0.008s 0:00.01 0.0%    0+0k 0+0io 0pf+0w
> >
> > Saludos
> >
> > Pablo
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