ISMEAR: Difference between revisions
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{{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. | 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. | ||
---- | ---- | ||
Please consider how-to guide to choose the optimal [[smearing technique]]. | |||
== Tag options == | |||
*{{ | *{{TAGO|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}}. | |||
*{{TAGO|ISMEAR|-1}}: Fermi smearing with width {{TAG|SIGMA}}. | |||
*{{TAGO|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 {{TAGO|ISPIN|2}} calculations). | |||
*{{TAGO|ISMEAR|-3}}: perform a loop over {{TAG|SMEARINGS}} parameters supplied in the {{FILE|INCAR}} file. | |||
*{{TAGO|ISMEAR|-4}}: Tetrahedron method without smearing. | |||
*{{TAGO|ISMEAR|-5}}: Tetrahedron method with Blöchl corrections without smearing. | |||
*{{TAGO|ISMEAR|-14}}: Tetrahedron method with Fermi-Dirac smearing {{TAG|SIGMA}}. | |||
*{{TAGO|ISMEAR|-15}}: Tetrahedron method with Blöchl corrections with Fermi-Dirac smearing {{TAG|SIGMA}}. | |||
{{NB|mind|Use a [[KPOINTS|Γ-centered '''k'''-mesh]] for the tetrahedron methods.|:}} | |||
== Related tags and articles == | |||
{{TAG|SIGMA}}, | |||
{{TAG|EFERMI}}, | |||
{{TAG|FERWE}}, | |||
{{TAG|FERDO}}, | |||
{{TAG|SMEARINGS}}, | |||
[[Smearing technique]], | |||
[[K-point integration]] | |||
{{sc|ISMEAR|Examples|Examples that use this tag}} | |||
[[Category:INCAR]] | [[Category:INCAR tag]][[Category:Electronic occupancy]][[Category:Electronic minimization]][[Category:Density of states]] |
Latest revision as of 10:34, 27 February 2025
ISMEAR = -15 | -14 | -5 | -4 | -3 | -2 | -1 | 0 | [integer]>0
Default: ISMEAR = 1
Description: ISMEAR determines how the partial occupancies fnk 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
Mind: Methfessel-Paxton can yield erroneous results for insulators because the partial occupancies can be unphysical.
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 forISPIN = 2
calculations).
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, EFERMI, FERWE, FERDO, SMEARINGS, Smearing technique, K-point integration