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I'm using paw-gga pp, with the following INCAR. I would like to do GGA + U calculation, what could be the possible problem that I am not getting the desirable result, and getting 1 miuB less than the expected, all the time??

ENCUT = 400
NSW = 50
IBRION = 2
ISIF = 3
LWAVE = .FALSE.
LCHARG = .FALSE.
ISPIN=2
VOSKOWN=1
LREAL = auto
MAGMOM = 2*0 2*4 2*4 4*-4 4*-4 12*4 38*0
LORBIT = 11
GGAU = .TRUE.
GGAUTYPE = 2
GGAUL = 2
GGAUU = 5.10
GGAUJ = 0.10
GGAUPRINT = 2
LMAXMIX = 4

appreciate your help.

by defining the LDAU* parameters as GGAU*, they are ignored (please check your OUTCAR file): the input tags have to be set exactly by the same name as given in the handbook, whether the calculation is LDAU or GGAU is only specified by the XC-type of the POTCAR you use.

Thanks very much. I understood that using paw-GGA PP, and using notations like LDAU*, is the way of GGA+U calculation. Kindly let me know if I am wrong.

the input parameters LDAU, LDAUL,... only are used by vasp to use the U corrections and to define the numerical values for U, the j and the l-splitting. They are not used to define which kind of XC (LDA,GGA,...) is used, this is exclusively done by the POTCAR (and the GGA-tag, if defined). When reading INCAR it is checked whether the sting "LDAU" (LDAUU,...) is defined in INCAR. Unless this string is matched precisely, the U-corrections are not taken into account at all.

I have a question about kind of pseudopotentials. Is it necessary to use PAW potentials to take into account the on site Coulomb interaction? Or ultra soft PP can also be used?

I think only PAW atomic data can be used to perform DFT+U calculations. The DFT+U calculations require a projection onto localized atomic orbitals used to calculate the occupancy matrices. The latter are also linked to the cutoff radius of the PAW spheres.

That's why you need PAW datasets.

Thank you for answer