[QE-users] Difference in Fermi energy by increasing k-points

[José Xavier]

Dear QE users,

I performed a calculation using 6x6x6 k-point in SCF (fixed occupations) and 10x10x10 in NSCF (tetrahedra occupations). The E fermi was equal to the HOMO value (1.04 eV). However, when I increase (e.g. 8x8x8 and 12x12x12, respectively) or decrease (e.g. 4x4x4 and 8x8x8) the number of k-points in each calculation, the E fermi (6.03 eV) and HOMO (1.04 eV) are quite different. 

Could someone explain to me why is this happening? 


Sincerely, 
José Xavier
Department of Biophysics and Pharmacology
Federal University of Rio Grande do Norte
Natal, Brazil