Approximation of constant relaxation time from Energy dependent relaxation time

[Aminul Haque]

Dear experts,

We know that It is possible to calculate energy dependent electron and hole relaxation time using the EPW code.

Now, I was wondering how we can approximate the constant relaxation time from this data, that can be used in other calculations (for example, electronic contribution to thermal conductivity).

A straightforward average over an energy window can be an option. But, since only electrons with energies close to the Fermi level contribute to transport, the choice of energy window seems to be important. Besides, the weight of the contribution of electrons with different energies can be different.

In this regard, could you please suggest some methods to approximate the constant relaxation time of electrons/holes systematically from the output of EPW?


Thanks,
Muhammad Aminul Haque
Department of Electrical and Electronic Engineering
University of Dhaka, Bangladesh