DFT+U: Difference between revisions
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*The values in ''LDAUL'', ''LDAUU'' and ''LDAUJ'' must be specified for all atomic species! | *The values in ''LDAUL'', ''LDAUU'' and ''LDAUJ'' must be specified for all atomic species! | ||
*The default value in ''LDAUL'' is 2, so do not forget to specify your correct values for this flag in your ''INCAR'' file! | *The default value in VASP for ''LDAUL'' is 2, so do not forget to specify your correct values for this flag in your ''INCAR'' file! | ||
*It is not meaningful to compare the total energies resulting from calculations with different ''U'' and/or ''J'' (c.q. ''U - J'' in case of Dudarev's approach). | *It is not meaningful to compare the total energies resulting from calculations with different ''U'' and/or ''J'' (c.q. ''U - J'' in case of Dudarev's approach). | ||
Revision as of 13:59, 25 October 2012
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To perform a DFT + U calculation using VASP you just have to add the following flags to your INCAR file:
GGA = PW | PB | LM | 91 | PE | RP | PS | AM → The value of this flag depens on the DFT functional you want to use)[1]
LDAU = .TRUE.
LDAUL = "value" → It specifies the l-quantum number for which the on-site interaction is added (1 = p ; 2 = d ; 3 = f).
LDAUU = "value" → It specifies the effective on-site Coulomb interaction parameters (U).
LDAUJ = "value" → It specifies the effective on-site Exchange interaction parameters (J).
LASPH = .TRUE. → VASP recommends to add this flag to the INCAR file when using gradient corrected functionals.
IMPORTANT NOTES:
- In VASP there are several DFT + U approaches that can be used. You can specify the one you want by setting the corresponding value in the flag LDAUTYPE = "value". The default approach in VASP is the one introduced by Dudarev et al. (LDAUTYPE = 2).[2] For further details on this flag, see the online VASP manual.[3]
- The values in LDAUL, LDAUU and LDAUJ must be specified for all atomic species!
- The default value in VASP for LDAUL is 2, so do not forget to specify your correct values for this flag in your INCAR file!
- It is not meaningful to compare the total energies resulting from calculations with different U and/or J (c.q. U - J in case of Dudarev's approach).