ISMEAR: Difference between revisions

Latest revision as of 07:45, 24 October 2025

ISMEAR = -15 | -14 | -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.

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 and kept fixed throughout run. Alternatively, you can also choose occupancies in the INCAR file with the tag FERWE (and FERDO for ISPIN = 2 calculations).

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.

ISMEAR = -14: Tetrahedron method with Fermi-Dirac smearing SIGMA.

ISMEAR = -15: Tetrahedron method with Blöchl corrections with Fermi-Dirac smearing SIGMA.

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

@@ Line 1: / Line 1: @@
-{{TAGDEF|ISMEAR|-5 {{!}} -4 {{!}} -3 {{!}} -2 {{!}} -1 {{!}} 0 {{!}} [integer]>0 |1}}
+{{TAGDEF|ISMEAR|-15 {{!}} -14 {{!}} -5 {{!}} -4 {{!}} -3 {{!}} -2 {{!}} -1 {{!}} 0 {{!}} [integer]>0 |1}}
 Description: {{TAG|ISMEAR}} determines how the partial occupancies ''f''<sub>n'''k'''</sub> are set for each orbital. {{TAG|SIGMA}} determines the width of the smearing in eV.
@@ Line 8: / Line 8: @@
 == Tag options ==
-*{{TAGO|ISMEAR|0|op=>}}: method of Methfessel-Paxton order {{TAG|ISMEAR}} with width {{TAG|SIGMA}}.
+*{{TAG|ISMEAR|0|op=>}}: method of Methfessel-Paxton order {{TAG|ISMEAR}} with width {{TAG|SIGMA}}.
 {{NB|mind|Methfessel-Paxton can yield erroneous results for insulators because the partial occupancies can be unphysical.|:}}
-*{{TAGO|ISMEAR|0}}: Gaussian smearing with width {{TAG|SIGMA}}.
+*{{TAG|ISMEAR|0}}: Gaussian smearing with width {{TAG|SIGMA}}.
-*{{TAGO|ISMEAR|-1}}: Fermi smearing with width {{TAG|SIGMA}}.
+*{{TAG|ISMEAR|-1}}: Fermi smearing with width {{TAG|SIGMA}}.
-*{{TAGO|ISMEAR|-2}}: Partial occupancies are read in from the {{FILE|WAVECAR}} or {{FILE|INCAR}} file, and kept fixed throughout run.
+*{{TAG|ISMEAR|-2}}: Partial occupancies are read in from the {{FILE|WAVECAR}} and kept fixed throughout run. Alternatively, you can also choose occupancies in the {{FILE|INCAR}} file with the tag {{TAG|FERWE}} (and {{TAG|FERDO}} for {{TAG|ISPIN|2}} calculations).
-:You can also choose occupancies with the tags {{TAG|FERWE}} and in case of spin-polarized calculations also {{TAG|FERDO}}.
-*{{TAGO|ISMEAR|-3}}: perform a loop over {{TAG|SMEARINGS}} parameters supplied in the {{FILE|INCAR}} file.
+*{{TAG|ISMEAR|-3}}: perform a loop over {{TAG|SMEARINGS}} parameters supplied in the {{FILE|INCAR}} file.
-*{{TAGO|ISMEAR|-4}}: Tetrahedron method without smearing.
+*{{TAG|ISMEAR|-4}}: Tetrahedron method without smearing.
-*{{TAGO|ISMEAR|-5}}: Tetrahedron method with Blöchl corrections without smearing.
+*{{TAG|ISMEAR|-5}}: Tetrahedron method with Blöchl corrections without smearing.
+*{{TAG|ISMEAR|-14}}: Tetrahedron method with Fermi-Dirac smearing {{TAG|SIGMA}}.
+*{{TAG|ISMEAR|-15}}: Tetrahedron method with Blöchl corrections with Fermi-Dirac smearing {{TAG|SIGMA}}.
 {{NB|mind|Use a [[KPOINTS|&Gamma;-centered '''k'''-mesh]] for the tetrahedron methods.|:}}
 == Related tags and articles ==
 {{TAG|SIGMA}},
+{{TAG|EFERMI}},
 {{TAG|FERWE}},
 {{TAG|FERDO}},
 {{TAG|SMEARINGS}},
-[[Smearing technique]]
+[[Smearing technique]],
 [[K-point integration]]