bzsym

The key "bzsym" specifies that the symmetry should be exploited for the construction of Wannier functions. If the key "bzsym" is present, two k-point files have to be present: The file w90kpts holds the entire Brillouin zone and the file kpts.xml the reduced part. The file kptsmap specifies the symmetry operations needed to map the k-points in kpts.xml on the k-points in w90kpts. Clearly, if bzsym is specified in the step for preparation of Wannier functions, it has to be specified also in subsequent steps, e.g. when the Wannier functions are plotted, because a consistent choice of gauge in the eigenvectors needs to be ensured between all steps.

The procedure to use symmetry in Wannier function calculations is explained here: Use of symmetry in Wannier function calculations