Naslov
Rationale for switching to nonlocal functionals in Density Functional Theory

Autori
Lazić, Predrag ; Atodiresei, N. ; Caciuc, V. ; Brako, Radovan ; Gumhalter, Branko ; Bluegel, S.

Izvornik
Journal of physics. Condensed matter (0953-8984) 24 (2012), 42; 424215, 8

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Density functional theory ; van der Waals interactions ; nonlocal functionals

Sažetak
The Density Functional Theory (DFT) has been steadily improving over the past few decades, becoming the standard tool for electronic structure calculations. The early local functionals (LDA) were eventually replaced by more accurate semi-local functionals (GGA) which are in use today. A major persisting drawback is the lack of the nonlocal correlation which is at the core of dispersive (van der Waals) forces, so that a large and important class of systems remains outside the scope of DFT. The vdW-DF correlation functional of Langreth and Lundqvist published in 2004 was the first nonlocal functional which could be easily implemented. Beyond expectations, the nonlocal functional have brought significant improvement to systems that were believed not to be sensitive to nonlocal correlations. In this paper we use the example of graphene nanodomes growing on Ir(111) surface, where with the increase of the size of the graphene islands the character of the bonding changes from strong chemisorption towards almost pure physisorption. We demonstrate how the seamless character of the vdW-DF functionals makes it possible to treat all regimes sefconsistently, proving to be a systematic and consistent improvement of DFT regardless of the nature of bonding. We also discuss the typical surface science example of CO adsorption on (111) surfaces of metals, which shows that the nonlocal correlation may also be crucial for strongly chemisorbed systems. We briefly discuss open questions, in particular the choice of the most appropriate exchange part of the functional. As the vdW-DF begins to appear implemented selfconsistently in a number of popular DFT codes, with numerical cost close to the GGA calculations, we draw the attention of the DFT community to the advantages and benefits of adoption of this new class of functionals.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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