GGA
GGA = PW | PB | LM | 91 | PE | RP | PS | AM
Default: GGA = type of exchange-correlation in accordance with the POTCAR file
Description: GGA specifies the type of generalized-gradient-approximation one wishes to use.
This tag was added to perform GGA calculation with pseudopotentials generated with conventional LDA reference configurations.
Possible options are:
PB Perdew -Becke PW Perdew -Wang 86 LM Langreth-Mehl-Hu 91 Perdew -Wang 91 PE Perdew-Burke-Ernzerhof RP revised Perdew-Burke-Ernzerhof AM AM05 (Ref. [49,50], VASP tests see Ref. [51]) PS Perdew-Burke-Ernzerhof revised for solids (PBEsol, see Ref. [52])
The tags AM (AM05) and PS (PBEsol) are only supported by VASP.5.X. The AM05 functional and the PBEsol functional are constructed using different principles, but both aim at a decent description of yellium surface energies. In practice, they yield quite similar results for most materials. Both are available for spin polarized calculations.