Category:DFT+U: Difference between revisions

Revision as of 19:21, 6 April 2022

Theoretical background

The semilocal LDA and GGA functionals often fail to describe systems with localized (strongly correlated) $d$ or $f$ -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 $d$ or $f$ atom a strong intra-atomic interaction in a simplified (screened) Hartree-Fock like manner ( $E_{\text{HF}}({\hat {n}})$ ), as an on-site replacement of the semilocal functional (double-counting term $E_{\text{dc}}({\hat {n}})$ ):

E_{\text{xc}}^{{\text{LDA/GGA}}+U}(n,{\hat {n}})=E_{\text{xc}}^{\text{LDA/GGA}}(n,{\hat {n}})+E_{\text{HF}}({\hat {n}})-E_{\text{dc}}({\hat {n}})

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

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).

Pages in category "DFT+U"

The following 7 pages are in this category, out of 7 total.

D

DFT+U: formalism

L

[anisimov:prb:91-1] V. I. Anisimov, J. Zaanen, and O. K. Andersen, Phys. Rev. B 44, 943 (1991).

[1]

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 == Theoretical background ==
-The semilocal LDA and GGA functionals often fail to describe systems with localized (strongly correlated) <math>d</math> and <math>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>d</math> or <math>f</math> atom a strong intra-atomic interaction in a simplified (screened) Hartree-Fock like manner (<math>E_{\text{HF}}(\hat{n})</math>), as an on-site replacement of the semilocal functional (double-counting term <math>E_{\text{dc}}(\hat{n})</math>):
+The semilocal LDA and GGA functionals often fail to describe systems with localized (strongly correlated) <math>d</math> or <math>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>d</math> or <math>f</math> atom a strong intra-atomic interaction in a simplified (screened) Hartree-Fock like manner (<math>E_{\text{HF}}(\hat{n})</math>), as an on-site replacement of the semilocal functional (double-counting term <math>E_{\text{dc}}(\hat{n})</math>):
 :<math>E_{\text{xc}}^{\text{LDA/GGA}+U}(n,\hat{n}) = E_{\text{xc}}^{\text{LDA/GGA}}(n,\hat{n}) + E_{\text{HF}}(\hat{n}) - E_{\text{dc}}(\hat{n})</math>
 where <math>\hat{n}</math>is the on-site occupancy matrix of the <math>d</math> or <math>f</math> electrons. This approach is commonly known as the DFT+U method{{cite|anisimov:prb:91|}} (traditionally called LSDA+U).
-== How to ==
+==How to==
 DFT+U can be used by specifying the tags {{TAG|LDAU}} and {{TAG|LDAUTYPE}} in the {{FILE|INCAR}} file.