Linear-Scaling ab-initio Calculations for Large and Complex Systems

Artacho, Emilio; Sánchez‐Portal, Daniel; Ordejón, Pablo; García, Antón; Soler, Josep M.

doi:10.1002/(sici)1521-3951(199909)215:1<809::aid-pssb809>3.0.co;2-0

Cited by 1,037 publications

(781 citation statements)

References 33 publications

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“…7,16,18,22 Different basis sets were used for the silicon atoms ͑see below for more details͒. For the fastest calculation, a single-͑SZ͒ basis of numerical atomic orbitals 43,47,48 was used. The SZ basis uses only one radial function to represent the orbitals in the 3s shell and another one for the 3p shell.…”

Section: A Density Functional Calculationsmentioning

confidence: 99%

Systematic investigation of the structure of the Si(553)-Au surface from first principles

Riikonen

Sánchez‐Portal

2008

Phys. Rev. B

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We present here a comprehensive search for the structure of the Si͑553͒-Au reconstruction. More than 200 different trial structures have been studied using first-principles density-functional calculations with the SIESTA code. An iterative procedure, with a step-by-step increase in the accuracy and computational cost of the calculations, was used to allow for the study of this large number of configurations. We have considered reconstructions restricted to the topmost bilayer and studied two types: ͑i͒ "flat" surface-bilayer models, where atoms at the topmost bilayer present different coordinations and registries with the underlying bulk, and ͑ii͒ nine different models based on the substitution of a silicon atom by a gold atom in different positions of a -bonded chain reconstruction of the Si͑553͒ surface. We have developed a compact notation that allows us to label and identify all these structures. This is very useful for the automatic generation of trial geometries and for counting the number of inequivalent structures, i.e., structures that have different bonding topologies. The most stable models are those that exhibit a honeycomb-chain structure at the step edge. One of our models ͑model "f2"͒ reproduces the main features of the room temperature photoemission and scanning-tunneling microscopy data. Thus, we conclude that this model is a good candidate for the high temperature structure of the Si͑553͒-Au surface.

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Section: A Density Functional Calculationsmentioning

confidence: 99%

Systematic investigation of the structure of the Si(553)-Au surface from first principles

Riikonen

Sánchez‐Portal

2008

Phys. Rev. B

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“…I have used here the generalized gradient approximation (GGA) to DFT [36,37], Troullier-Martins norm-conserving pseudopotentials [38], and a double-ζ polarized (DZP) basis set for all the atomic species [33,34,39]. A Brillouin zone sampling of 24 inequivalent k points, and a real-space grid equivalent to a plane-wave cutoff of 225 Ry (up to 82 k points and 300 Ry in the convergence tests) have been employed.…”

Section: Details Of Calculationsmentioning

confidence: 99%

First principles study of Si(3 3 5)–Au surface

Krawiec

2008

Applied Surface Science

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The structural and electronic properties of gold decorated Si(335) [12,14] and scanning tunneling microscopy (STM) [12,13]. In particular, STM topography data show a single monatomic chain on each terrace, which has been interpreted as the Si atoms with broken bonds at the step edge [12]. As the Au atoms are more electronegative than Si, they pair neighboring Si bond with their 6s, p electrons. As a result, a low-lying bound state, not visible to STM, is created. The STM

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“…Turning our attention to the basis set it is worth pointing out that SIESTA uses a flexible multiple-ζ basis set [34] of numerical atomic orbitals. Our calculations use double-ζ for the s and p-shells of any element and a triple-ζ basis set for the Mn 3d-shell.…”

Section: Computational Detailsmentioning

confidence: 99%

Different origins of the ferromagnetic order in (Ga,Mn)As and (Ga,Mn)N

2004

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The mechanism for the ferromagnetic order of (Ga,Mn)As and (Ga,Mn)N is extensively studied over a vast range of Mn concentrations. We calculate the electronic structures of these materials using density functional theory in both the local spin density approximation and the LDA+U scheme, that we have now implemented in the code SIESTA. For (Ga,Mn)As, the LDA+U approach leads to a hole mediated picture of the ferromagnetism, with an exchange constant N β= -2.8 eV. This is smaller than that obtained with LSDA, which overestimates the exchange coupling between Mn ions and the As p holes. In contrast, the ferromagnetism in wurtzite (Ga,Mn)N is caused by the double-exchange mechanism, since a hole of strong d character is found at the Fermi level in both the LSDA and the LDA+U approaches. In this case the coupling between the Mn ions decays rapidly with the Mn-Mn separation. This suggests a two phases picture of the ferromagnetic order in (Ga,Mn)N, with a robust ferromagnetic phase at large Mn concentration coexisting with a diluted weak ferromagnetic phase.

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Linear-Scaling ab-initio Calculations for Large and Complex Systems

Cited by 1,037 publications

References 33 publications

Systematic investigation of the structure of the Si(553)-Au surface from first principles

Systematic investigation of the structure of the Si(553)-Au surface from first principles

First principles study of Si(3 3 5)–Au surface

Different origins of the ferromagnetic order in (Ga,Mn)As and (Ga,Mn)N

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