Category:DFT+U: Difference between revisions
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where <math>\hat{n}</math> is the on-site occupancy matrix of the <math>d</math> or <math>f</math> electrons. This approach is known as the DFT+U method (traditionally called LSDA+U{{cite|anisimov:prb:91|}} ). | where <math>\hat{n}</math> is the on-site occupancy matrix of the <math>d</math> or <math>f</math> electrons. This approach is known as the DFT+U method (traditionally called LSDA+U{{cite|anisimov:prb:91|}} ). | ||
The first VASP DFT+U calculations, including some additional technical details on the VASP implementation, can be found in Ref. | 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 <ref name="Bengone:prb:00"/> and Georg Kresse). | ||
==How to== | ==How to== | ||
Revision as of 19:34, 6 April 2022
Theoretical background
The semilocal LDA and GGA functionals often fail to describe systems with localized (strongly correlated) [math]\displaystyle{ d }[/math] or [math]\displaystyle{ f }[/math]-electrons (this manifests itself primarily in the form of unrealistic one-electron energies and too small magnetic moments). In some cases this can be remedied by introducing on the [math]\displaystyle{ d }[/math] or [math]\displaystyle{ f }[/math] atom a strong intra-atomic interaction in a simplified (screened) Hartree-Fock like manner ([math]\displaystyle{ E_{\text{HF}}(\hat{n}) }[/math]), as an on-site replacement of the semilocal functional (double-counting term [math]\displaystyle{ E_{\text{dc}}(\hat{n}) }[/math]):
- [math]\displaystyle{ E_{\text{xc}}^{\text{LDA/GGA}+U}(n,\hat{n}) = E_{\text{xc}}^{\text{LDA/GGA}}(n) + E_{\text{HF}}(\hat{n}) - E_{\text{dc}}(\hat{n}) }[/math]
where [math]\displaystyle{ \hat{n} }[/math] is the on-site occupancy matrix of the [math]\displaystyle{ d }[/math] or [math]\displaystyle{ f }[/math] 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).
How to
DFT+U can be used by specifying the tags LDAU and LDAUTYPE in the INCAR file.
- ↑ V. I. Anisimov, J. Zaanen, and O. K. Andersen, Phys. Rev. B 44, 943 (1991).
- ↑ A. Rohrbach, J. Hafner, and G. Kresse J. Phys.: Condens. Matter 15, 979 (2003).
- ↑ Cite error: Invalid
<ref>tag; no text was provided for refs namedBengone:prb:00