BSE spectra showing very low eps values

[Ponnappa]

Dear Yambo Developers and users,
I was trying the BSE spectra for a 2D semiconducting material. I have obtained the spectra but have two concerns ragarding the same.

1) The eps values which are obtained are very low .

2) Inspite of being a semiconductor the spectra starts from non zero value.

I donot understand the reason behind this. I am attaching the input files of the 3 steps which I used (and the K points for BSE calculation 42*42*1) and the eps spectra . Looking forward for the response. Thank you in Advance.

Regards,
Ponnappa K. P.

[Ponnappa]

I have attached the eps spectra.

Regars,
Ponnappa

[Daniele Varsano]

Dear Ponappa,

1) The eps values which are obtained are very low:

please have a look at the FAQ:
https://www.yambo-code.eu/learn/#FAQs

2) Inspite of being a semiconductor the spectra starts from non zero value:

This is the effect of the Lorentzian smearing, if you reduce it you the non zero absorption at zero energy will disappear.

Best,

Daniele

[Ponnappa]

Dear Daniele Varsano,
Thank you, I could fix the problem with your suggestion.