[Wien] Relaxation time in BoltzTraP

[hiromasa_kaibe@komatsu.co.jp]

Dear Prof. Georg H.H.Madsen
Thank you for  providing us Boltztrap. It is really helpful for understanding
thermoelectricity.

I would like to ask you a question on relaxation time in BoltzTrap. You mentioned in
your article that "In the present we will use the simplest approximation for
relaxation time, namely to keep it cinstant, which is the most often used in praxis"
Does it mean the relaxation time is energy-independent and you handle it as a
constant value? Or you fixed scattering mode as for instance acoustic phonon or
something else?

Many thanks in advance,
Hiromasa Kaibe