ISPIN: Difference between revisions

Revision as of 11:03, 28 May 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. This is important for magnetic systems, where the two spin channels can have different occupations and energies. For nonmagnetic systems, spin polarization is often unnecessary and a non-spin-polarized calculation is sufficient.

ISPIN=1: non-spin-polarized calculations are performed. The spin-up and spin-down electrons are treated as identical.

ISPIN=2: spin-polarized collinear calculations are performed. The 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.

Important: For noncollinear calculations ISPIN is ignored. In VASP 6.5.0, the calculation exits with an error message 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.
-*{{TAG|ISPIN}}=2: spin-polarized calculations (collinear) are performed.
-By combining {{TAG|ISPIN}} with {{TAG|MAGMOM}} collinear magnetism can be studied.
+In spin-polarized calculations, VASP treats spin-up and spin-down electrons separately. This is important for magnetic systems, where the two spin channels can have different occupations and energies. For nonmagnetic systems, spin polarization is often unnecessary and a non-spin-polarized calculation is sufficient.
-{{NB|important| For noncollinear calculations {{TAG|ISPIN}} is ignored. In VASP 6.5.0, the calculation will exit with an error message if {{TAG|ISPIN}}{{=}}2 and {{TAG|MAGMOM}} is used in combination with the {{TAG|LNONCOLLINEAR}}{{=}}.TRUE.|}}
+*{{TAG|ISPIN}}=1: non-spin-polarized calculations are performed. The spin-up and spin-down electrons are treated as identical.
+*{{TAG|ISPIN}}=2: spin-polarized collinear calculations are performed. The 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}}.
+<syntaxhighlight lang="text">
+ISPIN = 2
+MAGMOM = 2*5.0 2*-5.0
+</syntaxhighlight>
+This example initializes two atoms with positive magnetic moments and two atoms with negative magnetic moments, which may be useful for antiferromagnetic calculations.
+{{NB|important|For noncollinear calculations {{TAG|ISPIN}} is ignored. In VASP 6.5.0, the calculation exits with an error message 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}}
 [[Category:INCAR tag]][[Category:Magnetism]]