modeling of scattering rates

[mishchenka]

Dear all,

My questions concerns modeling of scattering rates in complex semiconductor structures. It is known that when using EPW it is possible to obtain the scattering rates when setting the parameters scattering_rates = .true. and scattering_rates_serta = .true. or scattering_rates_0rta = .true. in the epw.in file. But when executing the iterative solution of the Boltzmann equation, i.e., when setting the parameter iterative_bte = .true. in the epw.in file, the result is the calculation of the electron relaxation time in inv_tau_mode and inv_taucb_mode files, which, as written in the program module io_transport.f90, lines 800 and 813, can be translated into scattering rates by multiplying the values obtained in the program by the factor 20670.6944033 to get the dimension 1/ps.
Then my first question concerns whether I understand correctly that the program EPW allows to calculate us the scattering rates in two ways: the first way is within the scattering_rates_serta or scattering_rates_0rta approximations, and the second way is more precise within the iterative solution of the Boltzmann equation, i.e. when is setting the parameter iterative_bte = .true.
The second question concerns how to obtain scattering rates as a function of mode-resolved, i.e. phonon modes, i.e. LO, LA, TO, TA, ZA and ZO. In the program module io_transport.f90, lines 784 and 814 the parameter imode is specified. Am I right to understand that the value of this parameter and determines the type of phonon mode. Then, if so, the question arises, what value of the parameter imode, the values of which change 1 to 6, what corresponds to the type of mode, i.e. LO, LA, TO, TA, ZA and ZO.

Thanks for the answer!

Best regards,
Mishchenka Valery