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L(S)DA+U and charge disproportionation problem

Posted: Tue Jan 08, 2008 8:05 pm
by againsmile
Dear all,

Recently, I try to reproduce the experimental result which is a charge disproportionation of CaFeO3.

To do this, I used LDA+U method but I cannot find two distinct Fe.

I set the two distinct Fe MagMom.(0.5 and 6). But after this calculation, their charge(d) and MagMom(d) is almost same. How can i seperate it? Are there any errors in this INCAR file?

SYSTEM = CaFeO3_monoclinic_2kinds ordered magnetic
ISTART = 0; ICHARG = 2
ISMEAR = 1; SIGMA = 0.2
ISIF = 3
PREC = NORMAL
IBRION = 2
NSW = 49
ISPIN =2
MAGMOM = 16*0.5 8*6 8*0.5 48*0.5 ==>16:Ca, Fe1:8, Fe2:8, O:48
LWAVE = .FALSE.
LCHARG = .TRUE.
LREAL = .TRUE.
# ENCUT = 875
LDAU = .TRUE.
LDAUTYEPE = -1 2 -1
LDAUU = 0 6 0
LDAUJ = 0 1 0
LORBIT = 11
LMAXMIX = 4
ISYM = 0

L(S)DA+U and charge disproportionation problem

Posted: Mon Jan 28, 2008 9:48 am
by admin
Your INCAR file looks ok; please check if it may be necessary to increase the required accuracy.
Depending on the vasp version you use, it may help to define 2 different Fe types in POSCAR, add the Fe pseudopotential twice in POTCAR, and define all LDApU parameters as if there were 2 different Fe atom types.