The SIESTA DFT software provides to incorporate a Monkhorst-Pack k grid in DFT calculations. However to use the results with the BoltzTraP2 software, a Gamma centered k-grid with uniform distribution is required. Has anyone had any experience with this kind of a problem for 1D and 2D systems?
The siesta kgrid specification looks like this:
%block kgrid.MonkhorstPack <int> <int> <int> <offset> <int> <int> <int> <offset> <int> <int> <int> <offset> %endblock kgrid.MonkhorstPack
What $\Gamma$ centered means is that the offsets are all $0.$.
For some systems it may be beneficial to use non-centered grids to reduce the total number of k-points due to symmetries. However, if BoltzTraP2 requires the $\Gamma$ centered variant, simply do as above and set
<offset> to $0.$ for each direction.
Here an example with
NA, NB, NC being the number of k-points along each reciprocal lattice vector:
%block kgrid.MonkhorstPack NA 0 0 0. 0 NB 0 0. 0 0 NC 0. %endblock kgrid.MonkhorstPack
For details related to their meaning see here.