[Wien] opticcpara crashed for mstar

Tue Mar 9 18:43:28 CET 2021

Dear Bhamu,

to get a VBM k-point index, you would need to look for "0.383706" in your case.energyso and see which k-point this eigenvalue belongs to. For CBE, look for "0.401998" (it can be a different k-point).

In Si VBM is at Gamma, and CBM is far away from Gamma. Thus we have two different k-points. After some trials, I found that 7x7x7 unshifted k-mesh "hits" CBM of Si quite precisely.

Of course you need to be confident that the selected k-mesh "hits" the relevant extremum (extrema) of your band structure. For instance if you need Gamma, do not select a shifted mesh. When the extremum is away from the high-symmetry points and coordinates are known, it might be easier to use case.klist_band and target the point(s) of interest.

I hope it helps
Oleg

________________________________________
From: Wien <wien-bounces at zeus.theochem.tuwien.ac.at> on behalf of Dr. K. C. Bhamu <kcbhamu85 at gmail.com>
Sent: Tuesday, March 9, 2021 08:15
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] opticcpara crashed for mstar

Dear Prof. Oleg
Sorry for the late reply. As we have the opposite time zone so I am replying according to your office time.

My previous information was from pbe.spaghetti_ene.

Here is the relevant part from case.scf.

         Bandranges (emin - emax) and occupancy:
:BAN00066:  66    0.218900    0.284902  1.00000000
:BAN00067:  67    0.281755    0.322256  1.00000000
:BAN00068:  68    0.281755    0.322256  1.00000000
:BAN00069:  69    0.287914    0.335582  1.00000000
:BAN00070:  70    0.287914    0.335582  1.00000000
:BAN00071:  71    0.294157    0.351734  1.00000000
:BAN00072:  72    0.294157    0.351734  1.00000000
:BAN00073:  73    0.301071    0.368987  1.00000000
:BAN00074:  74    0.301071    0.368987  1.00000000
:BAN00075:  75    0.340059    0.383706  1.00000000
:BAN00076:  76    0.340059    0.383706  1.00000000  VBM
:BAN00077:  77    0.401998    0.551266  0.00000000  CBM
:BAN00078:  78    0.401998    0.551266  0.00000000
:BAN00079:  79    0.472834    0.603663  0.00000000
:BAN00080:  80    0.472834    0.603663  0.00000000
:BAN00081:  81    0.556737    0.634231  0.00000000
        Energy to separate low and high energystates:   -0.57035

Just above this part, I see
:KPT   :      NUMBER OF K-POINTS:     40
   0.0   0.0 angle (M,z), angle (M,x) deg

        SPIN-ORBIT EIGENVALUES:
     K=   0.14286   0.14286   0.14286     1  (In case of "Si" it is 0 0 0 so you took KP =1?)
      MATRIX SIZE=  552   WEIGHT= 8.00

Does it mean that I should look for #KP 1? and then of course, bandinxed 75,76 for VBM and CBM, respectively.
But in case of Si, you took #KP =1 for VBM and #KP=15 for CBM.
So now the band index is clear to me.

My next query is, how can I know #KP for VBM and CBM?

Sorry for the long conversation.

Thank you
Bhamu

On Mon, Mar 8, 2021 at 8:48 PM Rubel, Oleg <rubelo at mcmaster.ca<mailto:rubelo at mcmaster.ca>> wrote:
Dear Bhamu,

it seems you have k-point index=38, band index=653. To be on a safe side, I would look for band ranges (":BANXXX") in case.scf (last iteration). The occupancies are written down in the same table. If you have questions about interpretation of :BANXXX, it will be better if you list this section for your SCF file.

Thanks
Oleg

________________________________________
From: Wien <wien-bounces at zeus.theochem.tuwien.ac.at<mailto:wien-bounces at zeus.theochem.tuwien.ac.at>> on behalf of Dr. K. C. Bhamu <kcbhamu85 at gmail.com<mailto:kcbhamu85 at gmail.com>>
Sent: Sunday, March 7, 2021 08:09
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] opticcpara crashed for mstar

Dear Prof. Oleg
Sorry to interrupt you.
Earlier I was looking for the wrong file.
My case.klist has 40 k-points and thus #KP also varies upto 40.
>From my eigenvalue file, my VBM lies on band index=38 (XX)
row number   KP(YY)  ENE
653            1.08800    -0.04699
So according to your hint, I should look for #KP 653 and then index number 38.
But I have #KP upto 40.
You also mentioned occupancy, but I could not understand it.

Could you please correct me?

Thank you in advance.
Regards
Bhamu

On Thu, Mar 4, 2021 at 10:51 PM Rubel, Oleg <rubelo at mcmaster.ca<mailto:rubelo at mcmaster.ca><mailto:rubelo at mcmaster.ca<mailto:rubelo at mcmaster.ca>>> wrote:
Oh, sorry about the misunderstanding. In your previous correspondence it sounded as you had a confusion about which klist file is used.

> In my case the CBM/CMB is at N-point which is located at 622 row number in case.klist_band. But I have only 20 K-points in my case.klist and thus the total KP in mstar output file is also 20.

To get band edges, I would check an eigenvalues file to identify band number XX, k point number YY, occupancy. Then look for a line "# KP: YY" and band XX below that in the output of mstar.

I hope it answers the question
Oleg
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