Surfaces of silicon

Haneman, D.

doi:10.1088/0034-4885/50/8/003

Cited by 237 publications

(62 citation statements)

References 192 publications

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“…[74][75] To model the actual reconstructed surface, we relaxed the Si surface with KSDFT and employ the KSDFT-relaxed geometry in OFDFT calculations for comparison. Here, the surface reconstructs to form rows of non-alternately buckled dimers (p(2x1) symmetry); we realize that alternately buckled dimers may be slightly lower in energy [72][73][74][75][76][77] but such a state requires a p(2x2) periodic unit cell, which is more expensive to simulate. Since our goal is simply to compare KSDFT to OFDFT, this p(2x1) structure is sufficient.…”

Section: E Defect Formation Energiesmentioning

confidence: 99%

Density-decomposed orbital-free density functional theory for covalently bonded molecules and materials

Xia

Carter

2012

Phys. Rev. B

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We propose a density decomposition scheme using a Wang-Govind-Carter (WGC)-based kinetic energy density functional (KEDF) to accurately and efficiently simulate various covalently bonded molecules and materials within orbital free (OF) density functional theory (DFT). By using a local, density-dependent scale function, the total density is decomposed into a highly localized density within covalent bond regions and a flattened delocalized density, with the former described by semilocal KEDFs and the latter treated by the WGC KEDF. The new model predicts reasonable equilibrium volumes, bulk moduli, and phase ordering energies for various semiconductors compared to Kohn-Sham (KS) DFT benchmarks. The decomposition formalism greatly improves numerical stability and accuracy while retaining computational speed compared to simply applying the original WGC KEDF to covalent materials. The surface energy of Si (100) and various diatomic molecule properties can be stably calculated and also agree well with KSDFT benchmarks. This linear scaling, computationally efficient, density-partitioned/multi-KEDF scheme opens the door to large scale simulations of molecules, semiconductors, and insulators with OFDFT.2

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Section: E Defect Formation Energiesmentioning

confidence: 99%

Density-decomposed orbital-free density functional theory for covalently bonded molecules and materials

Xia

Carter

2012

Phys. Rev. B

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“…It has been used e.g. to measure the surface energy of mica [1], or to determine the weak plans in Silicon monocrystal [2], and estimate their surface energy [3]. As for fracture surfaces, scientists have also studied their morphology to improve their knowledge of the complex damage and fracture processes occurring at the microstructure scale during the failure of heterogeneous materials.…”

Section: Introductionmentioning

confidence: 99%

Cleaved surface ofi−AlPdMnquasicrystals: Influence of the local temperature elevation at the crack tip on the fracture surface roughness

2006

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Roughness of i-AlPdMn cleaved surfaces are presently analysed. From the atomic scale to 2-3 nm, they are shown to exhibit scaling properties hiding the cluster (0.45 nm) aperiodic structure. These properties are quantitatively similar to those observed on various disordered materials, albeit on other ranges of length scales. These properties are interpreted as the signature of damage mechanisms occurring within a 2-3 nm wide zone at the crack tip. The size of this process zone finds its origin in the local temperature elevation at the crack tip. For the very first time, this effect is reported to be responsible for a transition from a perfectly brittle behavior to a nanoductile one.

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“…1͑a͔͒ found on the Si-SiC ͑001͒ surfaces by low energy electron diffraction ͑LEED͒ [2][3][4] experiments are similar to those observed on the Si ͑001͒ surfaces. 34 Previous density functional theory ͑DFT͒ calculations with the local density approximation ͑LDA͒ 21 and generalized gradient approximation ͑GGA͒ 27 predicted that the 2ϫ1 dimer row structures are stable on the Si-SiC ͑001͒ surfaces, and the dimer geometries are unbuckled ͑symmetric͒. The dimer on the Si ͑001͒ surface was thought to have a buckled structure for the last decade, 34 -38 however, recent low temperature scanning tunneling microscopy ͑STM͒ observations suggest symmetric dimers.…”

Section: Introductionmentioning

confidence: 99%

Multiconfigurational self-consistent field study of the silicon carbide (001) surface

Tamura

Gordon

2003

The Journal of Chemical Physics

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Multiconfigurational self-consistent field calculations have been performed to investigate structural and electronic properties of cubic siliconcarbide (001) (SiC (001)) surfaces. The dimer on silicon-terminated SiC (001) (Si-SiC (001)) is found to be diradical in nature, due to destabilization of the π bond by bending the dimer. Since the SiClattice constant is larger than that of diamond, the >C=C< dimer on the carbonterminated SiC (001) (C-SiC (001)) surface is flatter and its π bond is stronger than those on diamond (001). The bridging dimer on the C-SiC (001) exhibits relatively small multiconfigurational character despite its bent geometry. H2adsorption onto the Si-SiC (001) diradical dimer is more favorable than that onto the partial π bonded Si (001) dimer. As the dimer geometry becomes flatter, the π bond becomes stronger and the H2adsorption on the dimer becomes less favorable. Multiconfigurational self-consistent field calculations have been performed to investigate structural and electronic properties of cubic silicon carbide ͑001͒ ͑SiC ͑001͒͒ surfaces. The dimer on silicon-terminated SiC ͑001͒ ͑Si-SiC ͑001͒͒ is found to be diradical in nature, due to destabilization of the bond by bending the dimer. Since the SiC lattice constant is larger than that of diamond, the ϾCvCϽ dimer on the carbon-terminated SiC ͑001͒ ͑C-SiC ͑001͒͒ surface is flatter and its bond is stronger than those on diamond ͑001͒. The bridging dimer on the C-SiC ͑001͒ exhibits relatively small multiconfigurational character despite its bent geometry. H 2 adsorption onto the Si-SiC ͑001͒ diradical dimer is more favorable than that onto the partial bonded Si ͑001͒ dimer. As the dimer geometry becomes flatter, the bond becomes stronger and the H 2 adsorption on the dimer becomes less favorable.

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Surfaces of silicon

Cited by 237 publications

References 192 publications

Density-decomposed orbital-free density functional theory for covalently bonded molecules and materials

Density-decomposed orbital-free density functional theory for covalently bonded molecules and materials

Cleaved surface ofi−AlPdMnquasicrystals: Influence of the local temperature elevation at the crack tip on the fracture surface roughness

Multiconfigurational self-consistent field study of the silicon carbide (001) surface

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