Silent fail in superlattice with U correction

[edith_simmen]

Good morning

I'm running calculations on a superlattice with 110 atoms and a U correction on the Ni atoms. For my current calculations, VASP silently fails when it calculates the occupancies and eigenvectors after some ionic relaxation steps, usually it always fails on the atoms close to the interface of the cell. I run the GPU version of VASP 6.6.1 and for the attached example, the calculation silently failed after 12 ionic relaxation steps. I have tried:

• How long it takes before it fails depends on the interface distance. But no matter what I choose, it eventually fails.

• With Vasp 6.6.1 and ISEARCH = 1 it runs longer before it fails compared to 6.5.1.

• Choosing more / less nodes or a different KPAR didn't help.

Do you know what this problem could be related to? I haven't figured out if it's related to a problem with VASP/the chosen calculation parameters or if the structure is just not feasible (I'm trying to include a supertetragonal BaTiO3 phase by constraining these atoms).

Thank you already in advance for your help!

Best,
Edith

[christopher_sheldon1]

Dear Edith,

Thank you for your question and your files. I am afraid that I was not able to repeat your issue. The calculation converged in 39 ionic steps. A few things that I changed in the INCAR:

ALGO = Normal
EDIFF = 1e-6 - converges quicker 1E-7 is very tight for this system
LDAUPRINT = 0 - limits the output
POTIM = 0.25 - so that the ionic steps are a little closer together

Unfortunately, the energies between ionic steps do change a lot between ionic steps. This indicates that there is a problem, likely with the DFT+U. I am still looking into this.

I will continue to investigate this. If you have a std.err file, could you provide it, along with your submission script? and I will try to replicate your issue.

Have you been able to repeat this on a smaller example? This would help me to determine where the issue is.

Best wishes,

Chris