Modified embedded-atom potentials for cubic materials and impurities

Baskes, M. I.

doi:10.1103/physrevb.46.2727

Cited by 1,867 publications

(1,342 citation statements)

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“…The original 1NN MEAM potential for Mo erroneously predicted that the high-density (110) surface would have a higher surface energy than the low-density (111) surface in bcc crystals. 10 The 2NN MEAM potential solved this problem by including the interactions between second nearest neighbors, whose distances are only about 15 % larger than the separations between the first nearest neighbors in bcc crystals. We chose Pt 3 Mo with a L1 2 structure as the reference structure to evaluate the cross-interaction potentials between Pt and Mo.…”

Section: Modeling Atomic Interactions In Pt-mo Alloy Systemsmentioning

confidence: 99%

“…11,23 The parameters of MEAM potentials for fcc Pt and bcc Mo were fitted to reproduce empirical data, namely cohesive energy, lattice constant, elastic constants, and vacancy formation energy. 10,22 The parameters of the MEAM cross potential between Pt and Mo were fitted to first-principles calculation results for Pt 3 Mo (L1 2 ). To obtain these first-principles calculation results, we evaluated the system energies using density-functional theory in the local density approximation.…”

Section: Modeling Atomic Interactions In Pt-mo Alloy Systemsmentioning

confidence: 99%

“…In this respect, the MEAM potentials have yielded better results than the original EAM potentials. 10 We report in Table 4 the calculated low-indexed surface energies for pure bcc Mo and fcc Pt using the developed MEAM potentials. These results show a good agreement in surface energies among the MEAM 5 potentials, results from another first-principles study 28 and experimental results.…”

Section: Modeling Atomic Interactions In Pt-mo Alloy Systemsmentioning

confidence: 99%

“…Furthermore, we tested our MEAM potentials by calculating the segregation profiles for (111) 10 . To simulate extended surfaces, we used slab simulation cells in which periodic boundary conditions are only applied in the two directions parallel to the surface and with fixed cell dimensions in those directions.…”

Section: Modeling Atomic Interactions In Pt-mo Alloy Systemsmentioning

confidence: 99%

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Surface Structures of Cubo-Octahedral Pt−Mo Catalyst Nanoparticles from Monte Carlo Simulations

et al. 2005

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-The surface structures of cubo-octahedral Pt-Mo nanoparticles have been investigated using the Monte Carlo method and modified embedded atom method potentials that we developed for Pt-Mo alloys. The cubo-octahedral Pt-Mo nanoparticles are constructed with disordered fcc configurations, with sizes from 2.5 to 5.0 nm, and with Pt concentrations from 60 to 90 at. %. The equilibrium Pt-Mo nanoparticle configurations were generated through Monte Carlo simulations allowing both atomic displacements and element exchanges at 600 K. We predict that the Pt atoms weakly segregate to the surfaces of such nanoparticles. The Pt concentrations in the surface are calculated to be 5 to 14 at. % higher than the Pt concentrations of the nanoparticles. Moreover, the Pt atoms preferentially segregate to the facet sites of the surface, while the Pt and Mo atoms tend to alternate along the edges and vertices of these nanoparticles. We found that decreasing the size or increasing the Pt concentration leads to higher Pt concentrations but fewer Pt-Mo pairs in the Pt-Mo nanoparticle surfaces.

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Section: Modeling Atomic Interactions In Pt-mo Alloy Systemsmentioning

confidence: 99%

Section: Modeling Atomic Interactions In Pt-mo Alloy Systemsmentioning

confidence: 99%

Section: Modeling Atomic Interactions In Pt-mo Alloy Systemsmentioning

confidence: 99%

Section: Modeling Atomic Interactions In Pt-mo Alloy Systemsmentioning

confidence: 99%

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Surface Structures of Cubo-Octahedral Pt−Mo Catalyst Nanoparticles from Monte Carlo Simulations

et al. 2005

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“…Examples include the MEAM [10], which incorporates angular effects in a way which uses only quantities already calculated in central-force molecular dynamics models, and the two-band model which describes the electronic state of each atom in an analytically solvable form [14].…”

Section: Introductionmentioning

confidence: 99%

Two-band second moment model for transition metals and alloys

Ackland

2006

Journal of Nuclear Materials

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A semi-empirical formalism based on the second moment tight binding approach, considering two bands is presented for deriving interatomic potentials for magnetic d-band materials. It incorporates an empirical local exchange interaction, which accounts for magnetic effects without increasing the computing time required for force evaluation. The consequences of applying a two-band picture to transition metal alloys and transition metal impurities is examined, which combined with evidence from ab initio calculations leads to some surprisingly simplifying conclusions. IntroductionSemiempirical models for metallic binding have had a long and successful history in computer modelling. The distinguishing features of models for metallic bonding are that they are shortranged and non-pairwise. The first of these features arises from the strong screening of the nuclear charge by the mobile electrons, the second arises from the delocalisation of those electrons.The most significant development in accounting for many body effect came in the mid eighties with the implementation of 'embedded atom' potentials (EAM) [4] (based loosely on density functional theory [5]) and 'Finnis-Sinclair' potentials (FS) [6] (based on the tight binding second moment approximation [7]). The two models have very similar computational requirements, and the names are often used interchangably, however there are some distinctions which come to the fore when considering multicomponent alloys.To highlight the differences, the energy according to the EAM is written:Where i and j label atoms of element I and J respectively, V is a pairwise potential which depends on both species, F I and φ J are the embedding function and charge density which depend on one species only.In slight contrast, the FS approach implies:

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Platinum Segregation to the (111) Surface of Ordered Pt80Fe20: LEIS Results and Model Simulations

Creemers

Deurinck

1997

Surf. Interface Anal.

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Low‐energy ion scattering (LEIS) was used to study the surface composition of a Pt80Fe20(111) alloy surface as a function of temperature. From 700 K onwards, high enough for sufficient atomic mobility to attain equilibrium, the surface consists of nearly pure Pt. These results agree completely with the results from LEED I/V analysis by Beccat et al. [Surf. Sci. 238, 105 (1990)], who also evidenced a monotonic concentration profile over the three top layers, slight relaxations between those layers and a (2×2) superstructure caused by an ordered atomic arrangement in the second layer. Simple expressions for the entropy changes upon segregation in ordered alloys combined with constant pairwise bond energies clearly appear to be inadequate to describe the observed experimental facts. Even when combined with Monte Carlo simulations, the constant bond energies fail to correctly reproduce the results. Only when the Monte Carlo method is combined with the more refined (modified) embedded atom method (MEAM) for energy description of an alloy is satisfactory agreement with experiment obtained. © 1997 by John Wiley & Sons, Ltd.

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Modified embedded-atom potentials for cubic materials and impurities

Cited by 1,867 publications

References 37 publications

Surface Structures of Cubo-Octahedral Pt−Mo Catalyst Nanoparticles from Monte Carlo Simulations

Surface Structures of Cubo-Octahedral Pt−Mo Catalyst Nanoparticles from Monte Carlo Simulations

Two-band second moment model for transition metals and alloys

Platinum Segregation to the (111) Surface of Ordered Pt80Fe20: LEIS Results and Model Simulations

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