Is performing only a relaxation calculation (calculation='relax') sufficient for geometrical optimization in conducting a density functional theory (DFT) study of 2D slabs, such as in the case of a $2×2×1$ monolayer of $\mathrm{MoS}_2?$, or should I perform variable cell relaxation (calculation='vc-relax') too?


1 Answer 1


Ideally, you would want the x and y cell parameters to change (assuming the 2d material is in the XY plane), whilst the z cell parameter is kept fixed to prevent interaction between the slabs.

This freezing of the z cell parameter could be done by using:


along with the CELL block

cell_dofree = 'c'

As mentioned here under the cell_dofree tag

  • $\begingroup$ thank you @Atom $\endgroup$ Commented Apr 10 at 5:50

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .