EPW Forum

Dear Experts,
I am trying to calculate mobility of GaN using epw and I am just following the silicon example of epw school 2018.In the space of filkf and filqf ,I have uploaded the file containing BZ crystal coordinates is shown below,

kpt.txt
105 crystal
0.00 0.00 0.00 0.00952380952
0.09 0.00 0.00 0.00952380952
0.00 0.09 0.00 0.00952380952
0.00 0.00 0.09 0.00952380952
0.09 0.09 0.00 0.00952380952
0.09 0.00 0.09 0.00952380952
0.00 0.09 0.09 0.00952380952
0.09 0.09 0.09 0.00952380952
-0.09 0.00 0.00 0.00952380952
0.00 -0.09 0.00 0.00952380952
0.00 0.00 -0.09 0.00952380952
-0.09 -0.09 0.00 0.00952380952
-0.09 0.00 -0.09 0.00952380952
0.00 -0.09 -0.09 0.00952380952
-0.09 -0.09 -0.09 0.00952380952
0.09 -0.09 0.00 0.00952380952
-0.09 0.09 0.00 0.00952380952
-0.09 0.00 0.09 0.00952380952
0.09 0.00 -0.09 0.00952380952
0.00 -0.09 0.09 0.00952380952
0.00 0.09 -0.09 0.00952380952
-0.09 0.09 0.09 0.00952380952
0.09 -0.09 0.09 0.00952380952
0.09 0.09 -0.09 0.00952380952
-0.09 -0.09 0.09 0.00952380952
-0.09 0.09 -0.09 0.00952380952
0.09 -0.09 -0.09 0.00952380952
0.02 0.00 0.00 0.00952380952
0.00 0.02 0.00 0.00952380952
0.00 0.00 0.02 0.00952380952
0.02 0.02 0.00 0.00952380952
0.02 0.00 0.02 0.00952380952
0.00 0.02 0.02 0.00952380952
0.02 0.02 0.02 0.00952380952
-0.02 0.00 0.00 0.00952380952
0.00 -0.02 0.00 0.00952380952
0.00 0.00 -0.02 0.00952380952
-0.02 -0.02 0.00 0.00952380952
-0.02 0.00 -0.02 0.00952380952
0.00 -0.02 -0.02 0.00952380952
-0.02 -0.02 -0.02 0.00952380952
0.02 -0.02 0.00 0.00952380952
-0.02 0.02 0.00 0.00952380952
-0.02 0.00 0.02 0.00952380952
0.02 0.00 -0.02 0.00952380952
0.00 -0.02 0.02 0.00952380952
0.00 0.02 -0.02 0.00952380952
-0.02 0.02 0.02 0.00952380952
0.02 -0.02 0.02 0.00952380952
0.02 0.02 -0.02 0.00952380952
-0.02 -0.02 0.02 0.00952380952
-0.02 0.02 -0.02 0.00952380952
0.02 -0.02 -0.02 0.00952380952
0.03 0.00 0.00 0.00952380952
0.00 0.03 0.00 0.00952380952
0.00 0.00 0.03 0.00952380952
0.03 0.03 0.00 0.00952380952
0.03 0.00 0.03 0.00952380952
0.00 0.03 0.03 0.00952380952
0.03 0.03 0.03 0.00952380952
-0.03 0.00 0.00 0.00952380952
0.00 -0.03 0.00 0.00952380952
0.00 0.00 -0.03 0.00952380952
-0.03 -0.03 0.00 0.00952380952
-0.03 0.00 -0.03 0.00952380952
0.00 -0.03 -0.03 0.00952380952
-0.03 -0.03 -0.03 0.00952380952
0.03 -0.03 0.00 0.00952380952
-0.03 0.03 0.00 0.00952380952
-0.03 0.00 0.03 0.00952380952
0.03 0.00 -0.03 0.00952380952
0.00 -0.03 0.03 0.00952380952
0.00 0.03 -0.03 0.00952380952
-0.03 0.03 0.03 0.00952380952
0.03 -0.03 0.03 0.00952380952
0.03 0.03 -0.03 0.00952380952
-0.03 -0.03 0.03 0.00952380952
-0.03 0.03 -0.03 0.00952380952
0.03 -0.03 -0.03 0.00952380952
0.47 0.00 0.00 0.00952380952
0.00 0.47 0.00 0.00952380952
0.00 0.00 0.47 0.00952380952
0.47 0.47 0.00 0.00952380952
0.47 0.00 0.47 0.00952380952
0.00 0.47 0.47 0.00952380952
0.47 0.47 0.47 0.00952380952
-0.47 0.00 0.00 0.00952380952
0.00 -0.47 0.00 0.00952380952
0.00 0.00 -0.47 0.00952380952
-0.47 -0.47 0.00 0.00952380952
-0.47 0.00 -0.47 0.00952380952
0.00 -0.47 -0.47 0.00952380952
-0.47 -0.47 -0.47 0.00952380952
0.47 -0.47 0.00 0.00952380952
-0.47 0.47 0.00 0.00952380952
-0.47 0.00 0.47 0.00952380952
0.47 0.00 -0.47 0.00952380952
0.00 -0.47 0.47 0.00952380952
0.00 0.47 -0.47 0.00952380952
-0.47 0.47 0.47 0.00952380952
0.47 -0.47 0.47 0.00952380952
0.47 0.47 -0.47 0.00952380952
-0.47 -0.47 0.47 0.00952380952
-0.47 0.47 -0.47 0.00952380952
0.47 -0.47 -0.47 0.00952380952

I want to have the correct weight of each row but here all the weights associated with every rows are equal.Please suggest me the procedure to obtain the correct weight.

Regards,
Anindya Bose

Dear Dr. Samuel Ponc ,
Can you please put your valuable comment on that.

Thanks and regards,
Anindya Bose

What you are providing looks like a "uniform" G-centered mesh that, than each k-point has a similar weight. Since you have 105 points, the weight of each point is 1/105=0.00952380952

Best,
Roxana Margine

Dear Dr Roxana Margine,
I am not getting the correct mobility by taking this G centered mesh, can you please suggest me what should I choose here? Do I need to take fine grids(nkf,nqf) instead of filkf & filqf or random grid to achieve the convergence in mobility values?I am getting large values of mobility than expected.

Thanks and regards,
Anindya Bose

Dear Anindya Bose,

This mesh was used for the school to provide reasonable mobilities at a very low computational cost. The weights are incorrect and just corresponds to 1/(number of points).

However it should NOT be used for realistic calculations. You should use homogeneous grids or other grids with correct weights.

Best wishes,
Samuel

Dear Dr. Samuel Ponc,
I am having just one more query, if I use random grid here then just I need to give value in the card rand_nq, rand_nk but how can I define weights there.This will simply be rand_nq=10000 etc.Please suggest.

Thanks and regards,
Anindya Bose

Hello,

If you are using the rand_nq, rand_nk cards, then you do not need to specify the weights. The weights will be 1/number of points in this case.

Best wishes,
Samuel