Problem regarding k- and q meshes in examples

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inoka
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Joined: Sun Oct 16, 2016 5:41 pm
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Problem regarding k- and q meshes in examples

Post by inoka »

Dear epw community

I have a question regarding k- and q-meshes used in epw examples. In all of your test examples distributed with the package, have different ways of defining these: for example, GaN , Diamond and MgB2 has following and filkf and filqf have used different kind of meshes. I do not understand why they have different methods. Is there any technical/definition for the selection? Or is it the same results if we use much denser mesh as nkf1,nkf2,nkf3 ((for example 100 each) and denser nqf1,nqf2,nqf3 ((for example 100 each) without giving filkf and filqf? I very much appreciate your clarification.


Also we can find the k- and q- meshed from quantum espresso output files. Can we use them instead of generating them separately from(ex kgen.py)?


Also is the final answers depends on the shape or method of the path?


GaN:
filqf = 'gan_band.qpt'
nkf1 = 10
nkf2 = 10
nkf3 = 10


Diamond:
filqf = 'meshes/path.dat'
nkf1 = 50
nkf2 = 50
nkf3 = 50



MgB2:
mp_mesh_k = .true.
nkf1 = 20
nkf2 = 20
nkf3 = 20

nqf1 = 20
nqf2 = 20
nqf3 = 20


Further, I noticed that we can get both linewidth.phself and linewidth.elself in a single epw run by elecselfen = .true. , and phonselfen = .true.. But in the diamond example, there are epw1 and epw2 for linewidth.phself and linewidth.elself. ( Of course fermi energy is given in epw2, but we can find it from scf.out and input it in epw1??) Is it wrong?


I apologize if these are very basic. But I did not find any resources to solve this problems.

Thank you in advance

Inoka

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