ypp -e s 1

[kxzhou]

Dear all,
1) When generating exciton data using the command ypp -J 2D_WR_WC -e s 1, how should one calculate excitons at different transition momenta? I tried ypp -J 2D_WR_WC -e s 4, but it seems to produce identical results (still only qpt1). I also attempted ypp -J 2D_WR_WC -e s 1 -F ypp_exciton.in, but no input file was generated.
2) How can I further apply the scissor operator to the G0W0 energy? I want to adjust the bandgap to match experimental values for plotting band structures and BSE calculations.
Best,
Kexin

[Daniele Varsano]

Dear Kexin,

1) the correct syntax is:
ypp -s -b #qpt -J dir

2) I do not think it is implemented the possiblity to apply a further scissor, you can apply a global scissor to the KS gap to match the experiment.

Best,

Daniele

[kxzhou]

Dear Daniele,
Thank you for your response.
1) I generated the input file using the command ypp -s -b #qpt -J dir, but there doesn't seem to be an option to set the exciton momentum. Could you please clarify further?

ypp.png

2) How exactly should this be configured? Is this approach correct?-- Use KfnQPdb to read the computed G0W0 energies and fill in the difference between the G0W0 bandgap and the experimental bandgap in KfnQP_E.

Code: Select all

KfnQPdb= "E<./GW/ndb.QP"                  # [EXTQP BSK BSS] Database action
 % KfnQP_E
 0.300000 | 1.000000 | 1.000000 |        # [EXTQP BSK BSS] E parameters  (c/v) eV|adim|adim
%

Or should the DFT bands be corrected before the G0W0 calculation?
Kexin

[Daniele Varsano]

Dear Kexin,

sorry, I wrote a wrong command line. The correct one is:
ypp -e s -b #iq

where, iq is the index of q point you want to analyze. Clearly, you need to calculate finite momentum BSE before doing that.

2) You can try, but I do not think it will work. As stated, I do not think it is implemented what you are aiming to do. You can use KfnQP_E to correct the KS gap to match the experimental one.

Best,

Daniele