How to create Quantum Espresso databases for an electron-phonon calculation with Yambo (1st part)

Here I show step-by-step how to use Quantum espresso to calculate phonons and electron-phonon matrix-elements on a regular q-grid, with the final aim to allow Yambo to read these databases and calculate the temperature dependent correction to the electronic states.

I suggest to use Quantum Espresso v-6.1.0. I usually create first scf and nscf folders.

1) In scf I run a standard scf calculation choosing the k grid and setting force_symmorphic=.true. An *.save folder will be automatically created.
2) In the main directory I copy the previously created *.save directory and I run a dVscf calculation, meaning a phonon calculation setting the flag electron_phonon = ‘dvscf’, and a q grid equivalent to the k grid you used before.

&inputph
tr2_ph = 1e-16
prefix = '6HSiC'
fildvscf = '6HSiC-dvscf'
fildyn = '6HSiC.dyn'
electron_phonon = 'dvscf',
epsil = .true.
trans = .true.
ldisp = .true.
verbosity = 'high'
nq1=10, nq2 =10, nq3=2
/


3) In nscf folder I run an nscf calculation, setting the number of bands nbnd = … force_symmorphic=.true. and the same q grid as before. A *.save folder will be automatically created.
4) In the main directory I copy and then overwrite the previous *.save directory with the new one. Now I run an elph calculation setting electron_phonon = ‘yambo’, and the q grid.

&inputph
fildvscf = '6HSiC-dvscf'
fildyn = '6HSiC.dyn'
verbosity = 'high'
epsil = .true.
ldisp = .true.
tr2_ph = 1e-16
prefix = '6HSiC'
electron_phonon = 'yambo',
trans = .false.
nq1=10, nq2 =10, nq3=2
/

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