Electron transport relaxation time

[tz_sjtu]

Dear All,

I want to calculate the electron transport relaxation, which is generally different from the electron scattering lifetime with an additional velocity-related term. I am wondering is there a way to directly calculate it within EPW4.2?
In the EPW4.0 paper, it is stated that the velocity terms can be extracted through (i) finite differences and (ii) analytic derivatives in the local approximation. However, I can not find the way to obtain the velocity terms. Is there a way to directly access these velocity matrix element for each interpolated electronic state (only diagonal term will be good)?
If someone has solved these problems, can you share your experiences with me, I will appreciate it very much.

Thanks
Zhen Tong
UMJI-SJTU

[sponce]

Hello,

The velocities in the local approximation is the variable "dmef" in the code.

This is used for example in selfen_phon.f90

Note that I currently develop the new capability of computing electron transport within the Boltzmann equation using those velocities. It takes a bit of time to make it computationally efficient with symmetry support etc.

I expect/hope for a public release by the end of this year.

Best,

Samuel