ISPIN: Difference between revisions

Latest revision as of 14:20, 1 June 2026

ISPIN = 1 | 2
Default: ISPIN = 1

Description: ISPIN specifies whether a calculation is performed with or without spin polarization.

In spin-polarized calculations, VASP treats spin-up and spin-down electrons separately, allowing each spin channel to develop a different charge density and occupation. This is essential for magnetic systems; for nonmagnetic systems it is generally unnecessary and increases computational cost.

ISPIN=1: VASP performs a non-spin-polarized calculation. Spin-up and spin-down electrons share a single charge density.

ISPIN=2: VASP performs a spin-polarized collinear calculation. Spin-up and spin-down electrons are treated separately.

Spin-polarized calculations are commonly used for magnetic materials such as Fe, Co, Ni, and magnetic oxides. To initialize magnetic moments on atoms, combine ISPIN=2 with MAGMOM.

ISPIN = 2
MAGMOM = 2*5.0 2*-5.0

This example initializes two atoms with positive magnetic moments and two atoms with negative magnetic moments, which may be useful for antiferromagnetic calculations.

Mind: For noncollinear calculations, ISPIN is ignored; use LNONCOLLINEAR=.TRUE. instead.

Mind: Since VASP 6.5.0, the calculation exits with an error if ISPIN=2 and MAGMOM are used together with LNONCOLLINEAR=.TRUE.

@@ Line 1: / Line 1: @@
 {{TAGDEF|ISPIN|1 {{!}} 2|1}}
-Description: {{TAG|ISPIN}} specifies spin polarization.
+Description: {{TAG|ISPIN}} specifies whether a calculation is performed with or without spin polarization.
 ----
-*{{TAG|ISPIN}}=1: non-spin-polarized calculations are performed.
+In spin-polarized calculations, VASP treats spin-up and spin-down electrons separately, allowing each spin channel to develop a different charge density and occupation. This is essential for magnetic systems; for nonmagnetic systems it is generally unnecessary and increases computational cost.
-*{{TAG|ISPIN}}=2: spin-polarized calculations (collinear) are performed.
-By combining {{TAG|ISPIN}} with {{TAG|MAGMOM}} collinear magnetism can be studied.
+*{{TAG|ISPIN}}=1: VASP performs a non-spin-polarized calculation. Spin-up and spin-down electrons share a single charge density.
-{{NB|important| For noncollinear calculations, {{TAG|ISPIN}}{{=}}1 should be used. {{TAG|ISPIN}}{{=}}2 performs collinear calculations, which is incompatible with noncollinear. In VASP 6.5.0, the calculation will crash if {{TAG|ISPIN}}{{=}}2 is used in combination with the {{TAG|LNONCOLLINEAR}}{{=}}.TRUE.|}}
+*{{TAG|ISPIN}}=2: VASP performs a spin-polarized collinear calculation. Spin-up and spin-down electrons are treated separately.
+Spin-polarized calculations are commonly used for magnetic materials such as Fe, Co, Ni, and magnetic oxides. To initialize magnetic moments on atoms, combine {{TAG|ISPIN}}=2 with {{TAG|MAGMOM}}.
+ ISPIN = 2
+ MAGMOM = 2*5.0 2*-5.0
+This example initializes two atoms with positive magnetic moments and two atoms with negative magnetic moments, which may be useful for antiferromagnetic calculations.
+{{NB|mind|For noncollinear calculations, {{TAG|ISPIN}} is ignored; use {{TAG|LNONCOLLINEAR}}{{=}}.TRUE. instead.|:}}
+{{NB|mind|Since VASP 6.5.0, the calculation exits with an error if {{TAG|ISPIN}}{{=}}2 and {{TAG|MAGMOM}} are used together with {{TAG|LNONCOLLINEAR}}{{=}}.TRUE.|:}}
 == Related tags and articles ==
 {{TAG|MAGMOM}}
+{{TAG|LNONCOLLINEAR}}
-{{sc|ISPIN|Examples|Examples that use this tag}}
+{{sc|ISPIN|Howto|Examples that use this tag}}
 [[Category:INCAR tag]][[Category:Magnetism]]