PHON DIELECTRIC: Difference between revisions
No edit summary |
No edit summary |
||
| Line 7: | Line 7: | ||
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. | 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 {{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 | 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 <math>\mathbf{G}</math> 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 09:38, 20 July 2022
PHON_DIELECTRIC = [3x3 real]
| Default: PHON_DIELECTRIC | = None |
Description: PHON_DIELECTRIC sets the static dielectric tensor to be used for the dipole-dipole corrections in the computation of the phonon dispersion. This is only used when LPHON_POLAR=.TRUE.
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 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, LPHON_POLAR, PHON_BORN_CHARGES, PHON_G_CUTOFF