Density functionals from LDA to GGA

Ziesche, P.; Kurth, Stefan; Perdew, John P.

doi:10.1016/s0927-0256(97)00206-1

Cited by 163 publications

(83 citation statements)

References 48 publications

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“…More specifically, the spin-polarized general gradient approximation (GGSA [17]) was used, which is based on the PBE functional (Perdew-Burke-Ernzerhof [18]) for electron exchange correlations. It has earlier been shown that the spin-polarized GGA method will give more accurate energy values, as compared to the spin-polarized local density approximation (LDA) method [19][20][21]. The GGA method usually gives a better overall description of the electronic subsystem, compared to the more simple LDA corrections.…”

Section: Methodsmentioning

confidence: 99%

Effect of CVD diamond growth by doping with nitrogen

Yi-Ming

Larsson

2013

Theor Chem Acc

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The purpose with the present investigation has been to support and explain the experimental observation made regarding the enhancing effect by N doping on especially the diamond (100)-2 9 1 growth rate. Within the present study, also the commonly observed diamond (111) and (110) surfaces were included, all assumed to be H-terminated. Density functional theory calculations were used, based on a plane wave approach under periodic boundary conditions. It was shown that the surface H abstraction reaction is most probably the rate-limiting step during diamond growth. In addition, the results showed that it is N, substitutionally positioned within the upper diamond surface, that will cause the growth rate improvement, and not nitrogen chemisorbed onto the growing surface in the form of either NH (or NH 2 ). The here presented numerical value for the growth rate enhancement for the diamond (100)-2 9 1 surface is almost identical with the experimentally obtained one (3.7 vs. 3.6). In addition, the (111) and (110) surfaces were shown to undergo a different growth rate enhancement, with about half as much for the (111) and (110) surfaces as compared to the diamond (100)-2 9 1 surface (1.9, 1.7 vs. 3.7). Despite the rate improvement for all surface planes, this difference will bring about a preferred diamond (100) surface texture.

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Section: Methodsmentioning

confidence: 99%

Effect of CVD diamond growth by doping with nitrogen

Yi-Ming

Larsson

2013

Theor Chem Acc

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“…2 Here, we will simply mention that another alternative and efficient approach is the use of two-particle Green's functions that enables an accurate description of excitonic effects in semiconductors and simple ionic insulators such LiF. 9 The origin of the failure of the Hartree-Fock and LDA 10 to the LDA are required if one wishes to stay within the density-functional theory ͑DFT͒ description. Here we quote the selfinteraction-correction 11 and on-site Coulomb repulsion terms.…”

Section: Introductionmentioning

confidence: 99%

Core exciton energies of bulk MgO,Al2O3,and
Sousa
¹
,
Graaf
²
,
Illas
³

2000
Phys. Rev. B
17
1
5
0
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Ab initio cluster model wave functions are used to predict the existence of localized excited states in MgO, Al 2 O 3 , and SiO 2 arising from metal 2p core-level excitations. Theoretical values obtained at different levels of theory result in a quantitative agreement with experiment, and the use of different models permits us to quantify the different contributions to the final excitation energy. The most important contribution is atomic in nature; a meaningful zero-order approximation is that in MgO and Al 2 O 3 the exciton can be assigned to a M (2p 6 )→M (2p 5 3s 1 )-like excitation, where M ϭMg or Al. For the atomic models, the singlet-triplet exchange in the excited configuration is in good agreement with experiment. In addition, the solid-state effects on this exchange energy predicted by experiment are well reproduced by the cluster models representing MgO and SiO 2 , whereas a less clear situation appears in Al 2 O 3 . The open-shell orbital in the final state has, however, important contributions from the ions near the atomic site where excitation occurs. Nevertheless, the final state appears to be localized in space without any a priori assumption, the localization following from the holeparticle interaction implicitly induced in the final-state wave function. The Madelung field reduces the excitation energy with respect to the atomic value; the effect of neighboring atoms, mainly Pauli repulsion, acts in the opposite way; and electronic correlation effects decrease it again. In agreement with the covalent nature of SiO 2 , the exciton cannot be simply understood as arising from a Si(2p 6 )→Si(2p 5 3s 1 ) in a fully oxidized Si cation.

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“…Over the past about five decades DFT has been spectacularly successful in calculating material properties as well as designing novel materials with superior characteristics [2,3]. For many elements and compounds, the exchange correlation functionals required for DFT calculations can be satisfactorily described using the local density approximation (LDA), or generalized gradient approximation (GGA) achieving very good agreement with experimental data [4,5]. These standard approximations, however, fail to describe strongly correlated systems because of uncompensated self-interactions that introduce large errors.…”

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confidence: 99%