LPHON POLAR: Difference between revisions

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If the material is polar (i.e. has more than one atom type), a special treatment of the long-range dipole-dipole interaction is required to obtain a smooth phonon dispersion.
If the material is polar (i.e. has more than one atom type), a special treatment of the long-range dipole-dipole interaction is required to obtain a smooth phonon dispersion.
This is activated by setting {{TAG|LPHON_POLAR}}=.TRUE. and supplying the static dielectric tensor ({{TAG|PHON_DIELECTRIC}}) and the Born-effective charges ({{TAG|PHON_BORN_CHARGES}}) which can be obtained on a separate VASP run using the {{TAG|LEPSILON}} or {{TAG|LCALCEPS}} tag. The long-range part is evaluated using an Ewald sum with the number of G-vectors in reciprocal space being determined using a cutoff length ({{TAG|PHON_G_CUTOFF}}).
This is activated by setting {{TAG|LPHON_POLAR}}=.TRUE. and supplying the static dielectric tensor ({{TAG|PHON_DIELECTRIC}}) and the Born-effective charges ({{TAG|PHON_BORN_CHARGES}}) which can be obtained in a separate VASP calculation using the {{TAG|LEPSILON}} or {{TAG|LCALCEPS}} tag. The long-range part is evaluated using an Ewald sum with the number of G-vectors in reciprocal space being determined using a cutoff length ({{TAG|PHON_G_CUTOFF}}).
{{NB|mind| Only available as of VASP 6.3.2.}}
{{NB|mind| Only available as of VASP 6.3.2.}}



Revision as of 09:28, 20 July 2022

LPHON_POLAR = .TRUE. | .FALSE. 

Default: LPHON_POLAR = .FALSE.

Description: LPHON_POLAR includes dipole-dipole corrections in the computation of the phonon dispersion. For this mode, PHON_DIELECTRIC and PHON_BORN_CHARGES must also be set.


If the material is polar (i.e. has more than one atom type), a special treatment of the long-range dipole-dipole interaction is required to obtain a smooth phonon dispersion. This is activated by setting LPHON_POLAR=.TRUE. and supplying the static dielectric tensor (PHON_DIELECTRIC) and the Born-effective charges (PHON_BORN_CHARGES) which can be obtained in a separate VASP calculation using the LEPSILON or LCALCEPS tag. The long-range part is evaluated using an Ewald sum with the number of G-vectors in reciprocal space being determined using a cutoff length (PHON_G_CUTOFF).

Mind: Only available as of VASP 6.3.2.

Related tags and articles

QPOINTS, LPHON_DISPERSION, PHON_NWRITE, PHON_DIELECTRIC, PHON_BORN_CHARGES, PHON_G_CUTOFF

Examples that use this tag