self-energy sigma

[sdwang]

Dear developers:
When I read paper PRL 105, 026401 (2010), in it reference 15, there is a setence "G0W0 calculations employ the plasmon pole approximation
and include local-field effects in the dielectric function and self-energy sigma with an energy cutoff of 6 Ry."
I am confused the self-energy with cutoff of 6 Ry. In the input file of G0W0 , where can I set the self-energy?
In general, My procedure is:
>yambo -i
>yambo -x
>yambo -g n -p p

S D Wang

[myrta gruning]

"G0W0 calculations employ the plasmon pole approximation
and include local-field effects in the dielectric function and self-energy sigma with an energy cutoff of 6 Ry."
I am confused the self-energy with cutoff of 6 Ry. In the input file of G0W0 , where can I set the self-energy?

The authors refer to local-field effects. In the dielectric function those are controlled by the response block size, thus in Yambo by NGsBlkXp.
The dielectric function is then used for W in the self-energy, and I guess this is what the authors of that paper mean when they mention the cutoff for local field effects in the self-energy. In Yambo (yambo -g n -p p) you need just to specify NGsBlkXp (at least this is my interpretation).

Best,
m

[sdwang]

But why its unit is Ry?

[Daniele Varsano]

Hi Shudong,
you can set the cutoff in Rydberg, i.e. you can include all the Gvectors, such that
G^2/2 < E_cut(Ry). In order to do that you can replace the RL unit in the yambo input
with mHa (i.e. milli Hartree). 1Hartree=2Ry

Cheers,

Daniele