Dear all, I am facing something rather interesting. My system is an insulator supercell with a metallic impurity. I tried to converge the Fermi energy wrt. to k-points and smearing in particular for "low temperatures" (~20 K). I observed the following behavior for a chosen number of k-points (e.g. 6 6 6 0 0 0): with smaller smearing the fermi level approaches the same value as the fermi level using the tetrahedron method (i.e. the tet_opt method represents 0 Ry smearing).
however I found that for higher values for the k-point grid this does not seem to always work. For example for a 25 grid the value for the fermi level differs by ~0.8 eV! Is there a reason for this behavior? #k-grid kpnts Ef: smear tet 8 35 9.004 8.994 *25 455 8.974 8.201* 26 560 9.006 8.996 Your help is very much appreciated! Best wishes, Chris -- Postdoctoral Researcher Center for Quantum Nanoscience, Institute for Basic Science Ewha Womans University, Seoul, South Korea
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