Quantum ESPRESSO course for solid-state physics

1. Quantum ESPRESSO course for
solid-state physics
6. Hands-on tutorials of QE IV: Input generator
Nguyen Tuan Hung
Department of Materials Science and Engineering
National Taiwan University
https://nguyen-group.github.io/

2. Contents
 Band structure and phonon for a new material
- How to make vc-relax from a CIF file
- Energy band structure
- Phonon calculation
Ref: GitHub for input files
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3. https://github.com/nguyen-group/QE-SSP/
QE-SSP/cif2vc-relax cif_file
vc-relax
pseudo
SSSP_1.3.0_PBE_efficiency.json
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cif2vc-relax-2D.ipynb
cif2vc-relax-2D.py
cif2vc-relax-3D.ipynb
cif2vc-relax-2D.py
README.tex

4. (1) Preparing files
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Clone from GitHub:
$ git clone https://github.com/nguyen-group/QE-SSP.git
Download from: https://github.com/nguyen-group/QE-SSP/blob/master/cif2vc-relax.zip (only for this class)
For Python:
$ pip install ase
$ pip install cif2cell

5. (1) Find your cif file
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Some database that you can file any materials

6. (1) https://www.materialscloud.org/discover/mc2d/
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7. (1) https://www.materialscloud.org/discover/mc2d/
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8. (1) Run for convert CIF to vc-relax.in
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$ cd QE-SSP/cif2vc-relax
$ python3 cif2vc-relax-2D.py
$ vi vc-relax/vc-relax.in
???
???

9. (1) Rule to select ecutwfc and ecutrho
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$ vi SSSP_1.3.0_PBE_efficiency.json

10. (1) Rule to select k-point
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$ vi cif2vc-relax-2D.py
0.3 1/Å

11. (1) Make sure to have correct files on pseudo
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https://www.materialscloud.org/discover/sssp/table/efficiency

12. (1) Run vc-relax.in
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$ cd vc-relax
$ ./run.sh &
$ tail vc-relax.out

13. (2) Make input files for band structure
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$ cd ../
$ mkdir bands
$ cd bands
$ cp ../../gr/bands/run.sh ./
We need to make scf.in, nscf.in and
bands.in based on vc-relax.out

14. (2) Making scf.in
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vc-relax.in
‘scf’
Need to update from vc-relax.out
vc-relax.out

15. (2) Making scf.in
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16. (2) Making nscf.in
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nbnd = 20
‘bands’
vc-relax.out
nbnd should be >= Kohn-Sham states
How to find the k points for bands???

17. (2) Making nscf.in
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nbnd = 20
‘bands’
vc-relax.out
nbnd should be >=
Kohn-Sham states
How to find the k points for bands???

18. (2) Making nscf.in
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https://www.materialscloud.org/work/tools/seekpath

19. (2) Making nscf.in
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https://www.materialscloud.org/work/tools/seekpath

20. (2) Making nscf.in
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21. (2) Making bands.in
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It needs to be the same with scf.in and nscf.in
$ ./run.sh &

22. (2) Plotting band structure
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$ cp ../../gr/bands/plot-bands.ipynb
$ jupyter-lab plot-bands.ipynb

23. (2) Plotting band structure
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https://www.materialscloud.org/discover/mc2d/details/VSe2
The band structure of WSe2 has a spin up and
spin down, but our calculation is without spin.
 Do you want to do this homework??

24. (3) Phonon dispersion
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$ cd ../
$ mkdir phonon
$ cd phonon
$ cp ../../gr/phonon/run.sh ./
We need to make scf.in, ph.in,
q2r.in and matdyn.in

25. (3) Making scf.in
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$ cp ../bands/scf.in ./
To avoid soft phonon in 2D materials

26. (3) Making ph.in, q2r.in, matdyn.in
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same
with
scf.in
ph.in q2r.in
Correction for long-range
interaction (only QE >= v.7.2)
matdyn.in
Correction for long-
range interaction
same with nscf.in
$ ./run.sh &
$ tail ph.out

27. 27
https://qeinputgenerator.materialscloud.io/
Take-home message
Create input files
using web-based tool!