LPHON POLAR: Difference between revisions

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{{TAG | LPHON_DISPERSION}},
{{TAG | LPHON_DISPERSION}},
{{TAG | PHON_NWRITE}},
{{TAG | PHON_NWRITE}},
{{TAG | LPHON_POLAR}},
{{TAG | PHON_DIELECTRIC}},
{{TAG | PHON_DIELECTRIC}},
{{TAG | PHON_BORN_CHARGES}},
{{TAG | PHON_BORN_CHARGES}},

Revision as of 08:25, 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, PHON_BORN_CHARGES must also be set.


If the material is polar (i.e. has more than one different 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 on a separate VASP run 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