ISMEAR

ISMEAR = -5 | -4 | -3 | -2 | -1 | 0 | [integer]>0
Default: ISMEAR = 1 

Description: ISMEAR determines how the partial occupancies f_nk are set for each orbital. SIGMA determines the width of the smearing in eV.

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Please consider how-to guide to choose the optimal smearing technique.

Tag options

• ISMEAR > 0: method of Methfessel-Paxton order ISMEAR with width SIGMA.

Mind: Methfessel-Paxton can yield erroneous results for insulators because the partial occupancies can be unphysical.

• ISMEAR = 0: Gaussian smearing with width SIGMA.

• ISMEAR = -1: Fermi smearing with width SIGMA.

• ISMEAR = -2: Partial occupancies are read in from the WAVECAR or INCAR file, and kept fixed throughout run.

You can also choose occupancies with the tags FERWE and in case of spin-polarized calculations also FERDO.

• ISMEAR = -3: perform a loop over SMEARINGS parameters supplied in the INCAR file.

• ISMEAR = -4: Tetrahedron method without smearing.

• ISMEAR = -5: Tetrahedron method with Blöchl corrections without smearing.

Mind: Use a Γ-centered k-mesh for the tetrahedron methods.

Related tags and articles

SIGMA, FERWE, FERDO, SMEARINGS, Smearing technique, K-point integration

Examples that use this tag