KPointsGrid

KPointsGrid

Section Mesh::KPoints
Type block
Default $\backslash Gamma$-point only

When this block is given (and the KPoints block is not present), k-points are distributed in a uniform grid, according to a modified version of the Monkhorst-Pack scheme. For the original MP scheme, see James D. Pack and Hendrik J. Monkhorst, Phys. Rev. B 13, 5188 (1976) and Phys. Rev. B 16, 1748 (1977).

The number of columns should be equal to Dimensions, but the grid and shift numbers should be 1 and zero in finite directions.

The first row of the block is a set of integers defining the number of k-points to be used along each direction in reciprocal space. The numbers refer to the whole Brillouin zone, and the actual number of k-points is usually reduced exploiting the symmetries of the system. By default the grid will always include the $\Gamma$-point.

Optional rows can be added to specify multiple shifts in the k-points (between 0.0 and 1.0), in units of the Brillouin zone divided by the number in the first row. Please note that without specifying any shift, an implicit shift of -0.5 is added for odd number of k-points, such that the Gamma point is always included.

For example, the following input samples the BZ with 100 points in the xy-plane of reciprocal space:

%KPointsGrid
  10 | 10 | 1
%

is equivalent to

%KPointsGrid
10 | 10 | 1
0 | 0 | -0.5
%

 gamma_only_ = (parse_block(namespace, 'KPointsGrid', blk) /= 0)