QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: Changwei on November 15, 2018, 13:13

Title: 3D-material mobility
Post by: Changwei on November 15, 2018, 13:13

Hi,

I have already read the tutorial and accomplished calculating the mobility of graphene and some other 2D-materials. Recently my supervisor required me to calculate a 3D-material’s mobility and I was wondering if the electron-phonon-coupling calculation should contain k- and q-points on z-axis. If so, our computer can’t handle so many points.  Hence, how should I calculate 3D-material's mobility?

Besides, I also want to know how to judge if the k- and q-points are big and dense enough?

thanks

Title: Re: 3D-material mobility
Post by: Petr Khomyakov on November 15, 2018, 14:04

You may try using E-dependent method, as described in https://docs.quantumwise.com/tutorials/mobility/mobility.html.

Regarding the k- and q-grid density, it is a matter of convergence of the results with respect to the grid density, as usual for any numerical grid used in QuantumATK or any other code. Try to increase the grid density to see if that makes any difference.

Title: Re: 3D-material mobility
Post by: Changwei on November 30, 2018, 12:48

Thank you for your quick reply and apologize for my delay in responding.

I've already tried  E-dependent method but somehow the mobility matrix does not seem to be isotropic.

And, if the material is anisotropic, can I use the E-dependent method.

thanks

Title: Re: 3D-material mobility
Post by: Petr Khomyakov on December 3, 2018, 10:56

 See the benchmarks for "(k,q)-dependent method vs. energy-dependent method" in the tutorial I have mentioned in my previous reply. It is an approximation, and as any approximation it has its range of validity, so that, it has to be validated in one way or the other.

Title: Re: 3D-material mobility
Post by: Changwei on December 5, 2018, 08:40

Ok, thanks for your reply.