Calculate mobility or conductivity of 3-D bulk material

[fangyongxinxi]

Dir Sir,
I found "Phonon-limited mobility in graphene using the Boltzmann transport equation" in the tutorial, (https://docs.quantumwise.com/tutorials/mobility/mobility.html),  and found some discussion about  3-d material mobility calculation  (https://forum.quantumatk.com/index.php?topic=5928.msg25352#msg25352).

This is a alloy, and we found that in experiment :
1) in low temperature it has a ordered structure with conductivity a1,
2) in high temperature, the structure changed to amorphous, and the conductivity is a2.     
Now, we want to explain why the two structure (ordered structure and amorphous structure) have  quite different conductivity (a1, a2).

My questions are:
1) It's ok to use ATK to calculate the mobility or conductivity for 3-d material, such as my system metal alloy?
2) It's ok to use the mobility (calculate result) to compare to the experiment result ?

Thanks  for your time, and look forward to your reply.

Fangyong.
2020-5-7

[Tue Gunst]

Hi,
Yes, quantumatk mobility analysis can be done for 3d-materials.
We have published examples for
Systems of different dimensions (see fig. 8, incl. Silicon): https://arxiv.org/abs/1701.02883
A selection of bulk metals: https://arxiv.org/abs/1905.02794 and https://arxiv.org/abs/2001.02216

Calculations for 3D systems are more heavy than 2D and 1D systems.
For large disordered systems, such as amorphous structures, you could consider the special thermal displacement method instead: https://arxiv.org/abs/1706.09290
However, the mobility object offers more analysis options (contributions from individual modes for instance).

The precision of the simulations are equivalent to that of DFT. If the material of interest is accurately described by DFT (correct phonons and band structures) then you can expect the mobility to compare well to experiments probing the phonon-limited mobility.
If the experimental value extracted is limited by other processes (impurities or similar) you would need to perform a model for that scattering rate.
The mobility object allows you to include a user-given scattering rate on top of the electron-phonon coupling rate calculated by QuantumATK.