Thank you so much, Chris!
I had the impression that by using the Coulomb truncation, I might not need to worry about those electrostatic corrections. In fact, in another post where Ferenc replied to me, he mentioned that for some materials like perovskites, it is almost impossible to get the system to converge using those electrostatic corrections. So, if I choose not to use those corrections, I assume I would still need a large vacuum, but hopefully, the Coulomb truncation will help reduce the computational cost in the vacuum direction. Perhaps not?
By the way, I came across this information on the Quantum ESPRESSO documentation page. I am not entirely sure if it is related to the Coulomb truncation in VASP, but I would appreciate your thoughts on this. If you think there is a connection, should I follow the precautions outlined here? (https://www.quantum-espresso.org/Doc/INPUT_PW.html)
"'2D' :
Truncation of the Coulomb interaction in the z direction
for structures periodic in the x-y plane. Total energy,
forces and stresses are computed in a two-dimensional framework.
Linear-response calculations () done on top of a self-consistent
calculation with this flag will automatically be performed in
the 2D framework as well. Please refer to:
Sohier, T., Calandra, M., & Mauri, F. (2017), "Density functional
perturbation theory for gated two-dimensional heterostructures:
Theoretical developments and application to flexural phonons in graphene",
PRB, 96, 075448 (2017).
NB:
- The length of the unit-cell along the z direction should
be larger than twice the thickness of the 2D material
(including electrons). A reasonable estimate for a
layer's thickness could be the interlayer distance in the
corresponding layered bulk material. Otherwise,
the atomic thickness + 10 bohr should be a safe estimate.
There is also a lower limit of 20 bohr imposed by the cutoff
radius used to read pseudopotentials (see read_pseudo.f90 in Modules).
- As for ESM above, only in-plane stresses make sense and one
should use cell_dofree= '2Dxy' in a vc-relax calculation."
