8 votes

If Gaussian and Tetrahedron smearing method lead to different Fermi energies, which one is the correct?

ISMEAR=-5 gives you the correct Fermi energy. Usually, the Fermi level is set to the VBM. If you shift the BS by the Fermi energy from the DOS calculation with ISMEAR=-5, you will find your Fermi ...
Jack's user avatar
  • 15.1k
5 votes

Smearing values for different codes

The Fermi-Dirac function has a very long tail, so will tend to occupy states a long way above the Fermi level. This can mean that you need to include more conduction states in your calculation, in ...
Phil Hasnip's user avatar
  • 7,302
5 votes

Non-monotonic behaviour in calculation time with changing 'degauss' value of 'cold' smearing

I summarized our comments above into an answer that you should accept if it answers your question! :) The difference in simulation times is due to more or fewer SCF steps depending on ...
Tyler Sterling's user avatar
3 votes

Standard Practice for Relaxation, Band Structure and Density of States Calculations wrt smearing method

tetrahedron smearing(ISMEAR=-5) is not suitable for ionic relaxation because it introduces broadening of electronic energy levels, which can lead to inaccurate force evaluations and unphysical atomic ...
Pranav kumar's user avatar
  • 4,108
2 votes

How does one verify the density of states obtained using different smearing methods?

This paper "How to analyse a density of states" answers your question quite well I believe. Here's the "conclusion" of the paper. The density of states reveals striking features ...
CW Tan's user avatar
  • 1,276
1 vote

The "Tetrahedron method does not include variations of the Fermi occupations" Problem

The issue has been resolved. It seems that it was caused by rounding the cell parameters to the sixth digit after decimal point instead of printing all 16 digits of it. (I was applying some strain and ...
蕭力諶's user avatar
  • 411

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