Multilayer simulation of any material

[IndranilM]

In QW ATK, for multilayer simulation (let's assume n=4) of any material (multiple nanosheets of that material), Is the vacuum region consideration necessary (which is normally used to avoid periodic interaction during monolayer simulation)?? If so, what will be the approx vacuum region for above the 1st layer and below the nth layer (here, n=4)?

[mlee]

To avoid the artificial effect by periodic boundary condition, QuantumATK provides open boundary condition such as Dirichlet or Neumann boundary condition.
You can setup in the Poisson Solver.
The below manual explains different Poisson solvers.
https://docs.quantumatk.com/manual/includes/PoissonSolvers.html

Or you can build it with a long enough vacuum length using the periodic boundary condition. Honestly, it is hard to say what will be approximately vacuum region, because it depends on the configuration and surface dipole effect.

If you would like to confirm the vacuum state, HartreeDifferencePotential or ElectrostaticDifferencePotential analysis will be useful.

[IndranilM]

Thank you very much mlee for your reply.