How can I get the kpoints input file needed for the epw calc?

[jhosamelly]

In this tutorial https://drive.google.com/file/d/1wH16DL ... D6fG8/view exercise 2. There is a file LGXKG.txt. Based on the recording, I can use the tool https://www.materialscloud.org/work/tools/seekpath. However, when I tried to input the scf/nscf file there, it did not bring out the same kpoints as the one on the LGXKG.txt file. What can I do to get this file needed for my own calculation? Thank you.

[hpaudya1]

Hi jhosamelly,

You can do it by using pw.x, by printing list of kpoints along your path. Please follow the following steps.

Copy your scf.in to kpt.in and modify kpt.in as the following;
a) set verbosity = 'high' (if this is not set)
b) change K_POINTS {automatic} to
K_POINTS crystal_b
5
0.5000000000 0.5000000000 0.5000000000 40 ! L
0.0000000000 0.0000000000 0.0000000000 40 ! G
0.5000000000 0.0000000000 0.5000000000 40 ! X
0.3750000000 0.3750000000 0.7500000000 40 ! K
0.0000000000 0.0000000000 0.0000000000 1 ! G
(Note: you have 5 high symmetry points as listed above, 40 points between L-G, G-X, and so on)

(please make sure the coordinates of your high symmetry path is correct for the path you want)

c) Run (and kill after when it prints lists of k-points) your kpt.in using pw.x to $PATH-TO-YOUR-QE-bin/pw.x < kpt.in | tee kpt.out
d) Copy the lists of kpoints listed in kpt.out, as shown below
cryst. coord.
k( 1) = ( 0.5000000 0.5000000 0.5000000), wk = 0.0124224
k( 2) = ( 0.4875000 0.4875000 0.4875000), wk = 0.0124224
k( 3) = ( 0.4750000 0.4750000 0.4750000), wk = 0.0124224
k( 4) = ( 0.4625000 0.4625000 0.4625000), wk = 0.0124224
..........................
..........................
k( 160) = ( 0.0093750 0.0093750 0.0187500), wk = 0.0124224
k( 161) = ( 0.0000000 0.0000000 0.0000000), wk = 0.0124224

e) make LGXKG.txt as the following
161 crystal
0.5000000 0.5000000 0.5000000 0.0124224
0.4875000 0.4875000 0.4875000 0.0124224
0.4750000 0.4750000 0.4750000 0.0124224
0.4625000 0.4625000 0.4625000 0.0124224
..........................
..........................
0.0093750 0.0093750 0.0187500 0.0124224
0.0000000 0.0000000 0.0000000 0.0124224


I hope it helps.

Best,
Hari Paudyal

[jhosamelly]

Thank you for this!