Category:DFT+U: Difference between revisions
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The first VASP DFT+U calculations, including some additional technical details on the VASP implementation, can be found in Ref. {{cite|rohrbach:jcp:03}} (the original implementation was done by Olivier Bengone {{cite|Bengone:prb:00}} and Georg Kresse). | The first VASP DFT+U calculations, including some additional technical details on the VASP implementation, can be found in Ref. {{cite|rohrbach:jcp:03}} (the original implementation was done by Olivier Bengone {{cite|Bengone:prb:00}} and Georg Kresse). | ||
For more details, read the article about the [[DFT+U: formalism|formalism of the DFT+U method]]. | |||
==How to== | ==How to== |
Revision as of 05:59, 20 October 2023
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 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 LDA/GGA functional:
where is the double-counting term and 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).
For more details, read the article about the formalism of the DFT+U method.
How to
DFT+U can be switched on with the LDAU tag, while the LDAUTYPE tag determines the DFT+U flavor that is used. LDAUL specifies the -quantum number for which the on-site interaction is added, and the effective on-site Coulomb and exchange interactions are set (in eV) with the LDAUU and LDAUJ tags, respectively. Note that it is recommended to increase LMAXMIX to 4 for d-electrons or 6 for f-elements.