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# Category:DFT+U

The LDA and semilocal GGA functionals often fail to describe systems with localized (strongly correlated) or electrons (this manifests itself primarily in the form of unrealistic one-electron energies or too small magnetic moments in the case of systems with electrons). In some cases this can be remedied by introducing on the or atom a strong intra-atomic interaction in a simplified (screened) Hartree-Fock like manner (), as an on-site replacement of the semilocal functional (double-counting term ):

where is the on-site occupancy matrix of the or electrons. This approach is known as the DFT+U method (traditionally called LSDA+U^{[1]} ).

The first VASP DFT+U calculations, including some additional technical details on the VASP implementation, can be found in Ref. ^{[2]} (the original implementation was done by Olivier Bengone ^{[3]} and Georg Kresse).

More detail about the formalism of the DFT+U method can be found here.

## How to

DFT+U can be switched on with the LDAU tag in the INCAR file, while the LDAUTYPE tag determines the DFT+U flavor that is used.