The PAW potentials

PAW potential for all elements in the periodic table are available. With the exception of the 1st row elements, all PAW potentials were generated to work reliably and accurately at an energy cutoff of roughly 250 eV (the default energy cutoff is read by VASP from the POTCAR file, tag ENMAX in the POTCAR file). If you use any of the supplied PAW potentials you should include a reference to the following article:

P.E. Blöchl, Phys. Rev. B 50, 17953 (1994).
G. Kresse, and J. Joubert,
"From ultrasoft pseudopotentials to the projector augmented wave method",
Phys. Rev. B 59, 1758 (1999).

The distributed PAW potentials have been generated by G. Kresse following the recepies discussed in the second reference.

Generally the PAW potentials are more accurate than the ultra-soft pseudopotentials. There are two reasons for this: first, the radial cutoffs (core radii) are smaller than the radii used for the US pseudopotentials, and second the PAW potentials reconstruct the exact valence wave function with all nodes in the core region. Since the core radii of the PAW potentials are smaller, the required energy cutoffs and basis sets are also somewhat larger. If such a high precision is not required, the older US-PP can be used. In practice, however, the increase in the basis set size will be anyway small, since the energy cutoffs have not changed appreciably for C, N and O, so that calculations for models, which include any of these elements, are not more expensive with PAW than with US-PP.

For some elements several PAW versions exist. The standard version has generally no extension. An extension _h implies that the potential is harder than the standard potential and hence requires a larger energy cutoff. The extension _s means that the potential is softer than the standard version. The extensions _pv and _sv imply that the $p$ and $s$ semi-core states are treated as valence states ($i.e.$ for V_pv the $3p$ states are treated as valence states, and for V_sv the $3s$ and $3p$ states are treated as valence states). PAW files with an extension _d, treat the $d$ semi core states as valence states (for Ga_d the 3$d$ states are treated as valence states).

In the following sections, the PAW potentials are discussed in somewhat more detail.