Dear Peng Tao,
as Mohnish Pandey has reported, cell_dofree = 'xy' is not the right option for
you.
In recent versions of QE (I don't know if already in 5.0.2, for sure in the SVN
version) there is the
cell_dofree = '2Dxy'
option that allows the first two cell vectors to freely change on the pla
Dear all,
Recently, I just want to putting 'vc-relax' to optimize the graphene structure,
but it repots an error:
%%
from checkallsym : error # 2
not orthogonal operation
%
Dear Peng,
The cell you might be using is 'hexagonal' and the 'vc-relax' that you are
doing has two degrees of freedom in x and y direction which are orthogonal
due the flag 'cell_dofree = xy' you set. Since the symmetry is breaking in
the second step due to relaxation in x and y direction it is c
