[QE-users] K-Point Grid for Larger Crystals

[Stephen Zhang]

Hi Everyone,

I just wanted to ask about the sort of k-point grids one would use for
larger crystals (about 20 basis atoms). I've tried experimenting with
different k-point densities with the crystal Co3Sn2S2 (7 basis atoms), and
found that increasing the k-point grid density for scf calculations did not
change my fermi energy or total energy by much (the difference in fermi
energy between a 2x2x2 and a 16x16x16 grid was about 0.05eV). I've attached
a graph that shows the change in fermi energy with respect to the k-grid.
I'm just confused by this result since the crystal itself has over 20 atoms
in the unit cell, wouldn't a 2x2x2 grid not be enough to fully sample the
crystal given the number of orbitals present? Any thoughts?

Thanks,
Stephen

[image: index.png]

-- 
*University of California, Berkeley*
*Department of Letter and Sciences*
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