Different q-point weights in Pb calculation

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AgentZero
Posts: 44
Joined: Tue Jul 05, 2016 8:41 am
Affiliation:

Different q-point weights in Pb calculation

Post by AgentZero »

Dear all,

Recently, I compared the input files for Pb in EPW-2.3.6, EPW-3.0.0, and EPW-4.0.0.
And I found the q-point weights are different. For EPW-2.3.6/3.0.0, the weights are uniform (see below).
But for EPW-4.0.0, different q points have different weights.
Meanwhile, the q-point weights for GaN in EPW-4.0.0 are again uniform.
So, does the q-point weights (last column) in the input file make sense?
Does epw.x calculate the correct q-point weights itself inside the code?
Thank you very much for your help!

Best wishes,
Miao Gao
Ningbo University
-------------- q-point weight -----------------------
Pb, EPW-2.3.6/3.0.0
16 cartesian
0.0000000 0.0000000 0.0000000 0.0909090
-0.1666667 0.1666667 -0.1666667 0.0909090
-0.3333333 0.3333333 -0.3333333 0.0909090
0.5000000 -0.5000000 0.5000000 0.0909090
0.0000000 0.3333333 0.0000000 0.0909090
-0.1666667 0.5000000 -0.1666667 0.0909090
0.6666667 -0.3333333 0.6666667 0.0909090
0.5000000 -0.1666667 0.5000000 0.0909090
0.3333333 0.0000000 0.3333333 0.0909090
0.0000000 0.6666667 0.0000000 0.0909090
0.8333333 -0.1666667 0.8333333 0.0909090
0.6666667 0.0000000 0.6666667 0.0909090
0.0000000 -1.0000000 0.0000000 0.0909090
0.6666667 -0.3333333 1.0000000 0.0909090
0.5000000 -0.1666667 0.8333333 0.0909090
-0.3333333 -1.0000000 0.0000000 0.0909090

Pb, EPW-4.0.0, without SOC (or with SOC):
16 cartesian
0.000000000000 0.000000000000 0.000000000000 0.0092593
-0.166666666667 0.166666666667 -0.166666666667 0.0740741
-0.333333333333 0.333333333333 -0.333333333333 0.0740741
0.500000000000 -0.500000000000 0.500000000000 0.0370370
0.000000000000 0.333333333333 0.000000000000 0.0555556
-0.166666666667 0.500000000000 -0.166666666667 0.2222222
0.666666666667 -0.333333333333 0.666666666667 0.2222222
0.500000000000 -0.166666666667 0.500000000000 0.2222222
0.333333333333 0.000000000000 0.333333333333 0.1111111
0.000000000000 0.666666666667 0.000000000000 0.0555556
0.833333333333 -0.166666666667 0.833333333333 0.2222222
0.666666666667 0.000000000000 0.666666666667 0.1111111
0.000000000000 -1.000000000000 0.000000000000 0.0277778
0.666666666667 -0.333333333333 1.000000000000 0.2222222
0.500000000000 -0.166666666667 0.833333333333 0.2222222
-0.333333333333 -1.000000000000 0.000000000000 0.1111111

GaN (EPW-4.0.0)
28 cartesian
0.000000000 0.000000000 0.000000000 1
0.000000000 0.000000000 0.102242373 1
0.000000000 0.000000000 0.204484747 1
0.000000000 0.000000000 -0.306727120 1
0.000000000 0.192450090 0.000000000 1
0.000000000 0.192450090 0.102242373 1
0.000000000 0.192450090 0.204484747 1
0.000000000 0.192450090 -0.306727120 1
0.000000000 0.384900179 0.000000000 1
0.000000000 0.384900179 0.102242373 1
0.000000000 0.384900179 0.204484747 1
0.000000000 0.384900179 -0.306727120 1
0.000000000 -0.577350269 0.000000000 1
0.000000000 -0.577350269 0.102242373 1
0.000000000 -0.577350269 0.204484747 1
0.000000000 -0.577350269 -0.306727120 1
0.166666667 0.288675135 0.000000000 1
0.166666667 0.288675135 0.102242373 1
0.166666667 0.288675135 0.204484747 1
0.166666667 0.288675135 -0.306727120 1
0.166666667 0.481125224 0.000000000 1
0.166666667 0.481125224 0.102242373 1
0.166666667 0.481125224 0.204484747 1
0.166666667 0.481125224 -0.306727120 1
0.333333333 0.577350269 0.000000000 1
0.333333333 0.577350269 0.102242373 1
0.333333333 0.577350269 0.204484747 1
0.333333333 0.577350269 -0.306727120 1
sponce
Site Admin
Posts: 616
Joined: Wed Jan 13, 2016 7:25 pm
Affiliation: EPFL

Re: Different q-point weights in Pb calculation

Post by sponce »

Dear Miao Gao,

The q-points weight in the epw.in file are not used by EPW. Some number needs to be there for historical reasons but its not used. You can test this by changing the value and see that it does not change anything.

I will remove thsis for the next version of EPW. There will be no more the need to put the weight as this is very confusing.

Best,

Samuel
Prof. Samuel Poncé
Chercheur qualifié F.R.S.-FNRS / Professeur UCLouvain
Institute of Condensed Matter and Nanosciences
UCLouvain, Belgium
Web: https://www.samuelponce.com
AgentZero
Posts: 44
Joined: Tue Jul 05, 2016 8:41 am
Affiliation:

Re: Different q-point weights in Pb calculation

Post by AgentZero »

Dear Dr. Samuel Ponc,

Thank you very much for your reply. Could you please also give me some advice on
another question that I posted in the forum? This question is named "Extremely large values for nesting function".

Thanks again!

Best wishes,
Miao Gao
Ningbo University
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