[QE-users] scf calculation end without a crash file

[Z. Khatibi]

Dear all,

I've been struggling lately to produce electronic bands for my system. The
system is a slab of graphene/Tungsten di Selenide. The calculation
terminates at the very first stage of the computation (scf) without a crash
file in the output. The output and input files can be found in the
following link (G-WSe2.in/out):
https://drive.google.com/drive/folders/1trdcWUw7GKSw0zLQouxygpaKwOl7_2KM?usp=sharing

There are few points I'd like to share:
- I've tried simplifying the input file by reducing the unnecessary flags
in the input. This only helped with the continuation of the calculation
without reaching convergence.
- I've been successful producing bands for a similar system but with the
Molybdenum di Selenide layer as the substrate. I didn't have any issues
there so I suspected that the Tungsten di Selendie is the problem. Then I
tried the scf calculation for Tungsten di Selenide layer alone by
eliminating graphene atoms. See Wse2.in/out files in the link I mentioned
earlier.
- The system I'm interested in is practically a 2*1 supercell of 4:3
graphene/WSe2 cell. The QE recognizes it as you can see the following
statement in the output:
"Found symmetry operation: I + ( -0.5000 -0.5000  0.0000)
  This is a supercell, fractional translations are disabled"
The scf computation for the 4:3 unitcell runs smoothly with similar input
flags. Although I had to play with ecutrho and ecutwfc flags a little bit.
This is the first step to the computation of a disordered system therefore
I need to start with a 2*1 system.
- I suspected that the change of W pseudopotential might be an option but I
could not find any fully relativistic pbe PAW pps for W except the one I'm
using currently (pslibrary1.0.0).
- In a hopeless attempt, I set nosym to true and could see that it does not
converge but continues to calculate without abrupt termination (See
nosym.in/out files)

I've been reading the QE users' queries about convergence especially the
past few weeks and have tried lots of them for my case. Unfortunately, it
didn't lead to any success. So I really appreciate it if you can help me
with my calculation.

Kind regards,
--
Z. Khatibi
School of Physics
Trinity College Dublin
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