Efficient tight-binding approach for the study of strongly correlated systems

Simone Sanna, B. Hourahine, U. Gerstmann, Th. Frauenheim

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

In this work, we present results from self-consistent charge density functional based tight-binding (DFTB) calculational scheme, including local-density approximation +U (LDA+U) and simplified self-interaction-corrected-like potentials for the simulation of systems with localized strongly correlated electrons. This approach attempts to combine the efficiency of tight binding with the accuracy of more sophisticated ab initio methods and allows treatment of highly correlated electrons for very large systems. This is particularly interesting for the case of rare earths in GaN, where dilute amount of rare earth ions is used. In this work, we show the results of test calculations on bulk ErN and on the substitutional Er-Ga in wurtzite GaN, which we choose as representatives of bulk and point defects in solids with strongly correlated electrons. We find that ErN is a half metal in the ferromagnetic phase and that the substitutional Er-Ga in wurtzite GaN has C-3v symmetry. These examples show that the DFTB approach reproduces well the results of more demanding calculation schemes with a very low computational cost, making it suitable for the study of extended systems beyond the capabilities of density functional theory.

LanguageEnglish
Article number155128
Number of pages12
JournalPhysical Review B
Volume76
Issue number15
DOIs
Publication statusPublished - 30 Oct 2007

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wurtzite
Rare earths
Electrons
rare earth elements
Local density approximation
electrons
Point defects
Charge density
point defects
Density functional theory
Metals
Ions
density functional theory
costs
defects
symmetry
approximation
metals
Costs
ions

Keywords

  • density functional theory
  • electronic structure
  • self interaction
  • complex materials
  • Gallium Nitride
  • III-Nitrides
  • GaN
  • erbium
  • ER
  • simulations

Cite this

Sanna, Simone ; Hourahine, B. ; Gerstmann, U. ; Frauenheim, Th. / Efficient tight-binding approach for the study of strongly correlated systems. In: Physical Review B. 2007 ; Vol. 76, No. 15.
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Efficient tight-binding approach for the study of strongly correlated systems. / Sanna, Simone; Hourahine, B.; Gerstmann, U.; Frauenheim, Th.

In: Physical Review B, Vol. 76, No. 15, 155128, 30.10.2007.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Efficient tight-binding approach for the study of strongly correlated systems

AU - Sanna, Simone

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AU - Gerstmann, U.

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AB - In this work, we present results from self-consistent charge density functional based tight-binding (DFTB) calculational scheme, including local-density approximation +U (LDA+U) and simplified self-interaction-corrected-like potentials for the simulation of systems with localized strongly correlated electrons. This approach attempts to combine the efficiency of tight binding with the accuracy of more sophisticated ab initio methods and allows treatment of highly correlated electrons for very large systems. This is particularly interesting for the case of rare earths in GaN, where dilute amount of rare earth ions is used. In this work, we show the results of test calculations on bulk ErN and on the substitutional Er-Ga in wurtzite GaN, which we choose as representatives of bulk and point defects in solids with strongly correlated electrons. We find that ErN is a half metal in the ferromagnetic phase and that the substitutional Er-Ga in wurtzite GaN has C-3v symmetry. These examples show that the DFTB approach reproduces well the results of more demanding calculation schemes with a very low computational cost, making it suitable for the study of extended systems beyond the capabilities of density functional theory.

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