lifetime calculation

[samaneh]

Hi there,
Is there any possibility to calculate el-hole pair lifetime in YAMBO code?
Best
S. Ataei, University of Tehran, Iran

[Daniele Varsano]

Dear S. Atei,
at the moment it is not possible to calculate it.
Kind regards,
Daniele

[samaneh]

Dear Daniele,
Thanks a lot.
But another question
Are the results of lifetime calculation (in yambo)
for semiconductors reliable and in good agreement with
experiment?
Best regards
S. Ataei, University of Tehran, Iran

[Daniele Varsano]

Dear Atei,
comparison with experiment is always a delicate issue: depending on the system, are all the physical effects included in the theory?
For instances, depending on the system, electorn-phonon contribution could be relevant (please note that el-ph part of yambo is temporarily unavailable).
In any case I suggest you to have a look to this paper by Marini et al. on calculation of lifetimes done using yambo:
http://www.yambo-code.org/papers/cu-lifetimes.pdf

Best,
Daniele

[vitoversace]

Dear Daniele,

1) Does yambo take into account the real part of Z factor like equation 5 in the paper you mentioned above or ONLY the imaginary or sum of real and imaginary part of Z factor (Re Z + Im Z) for calculation of quasi particle life times ???

2) Why are in the paper in equations 3 and 4 self energy and Z factor given at quasi particle energies, i thought it should be at DFT energies, as you get Z factor when expanding sigma (omega=QP) around DFT energies !!!


Bests
Vito

[Daniele Varsano]

Dear Vito,
1) I suppose only real part is considered.
2) Because you consider as starting qp point the E_qp^0 and do the expansion. When you consider the KS energies as first guess, you will have Z=1 and obtain the on-mass-shell GW expression for the lifetime:
tau=1/(2 Im \Sigma (E_KS))

Best,
Daniele