The hidden mass of the universe

Firsov, O. B.

doi:10.1007/bf00559247

Cited by 10 publications

(13 citation statements)

References 10 publications

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“…Later, a purely local version of the BK theory was developed to take into account the charge distribution of the electrons 43,44 . Comparison with other electronic stopping models, such as Lindhard and Scharff 4 , Firsov 45 , and the above nonlocal implementation 42 , showed a marked improvement in modeling electronic stopping in the channel 7,43,44 . Good agreement between simulated dopant profiles and the SIMS profiles for boron implants into 100 single crystal silicon was obtained.…”

Section: Bca Monte Carlo Simulation Resultsmentioning

confidence: 90%

Phenomenological electronic stopping-power model for molecular dynamics and Monte Carlo simulation of ion implantation into silicon

et al. 1996

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It is crucial to have a good phenomenological model of electronic stopping power for modeling the physics of ion implantation into crystalline silicon. In the spirit of the Brandt-Kitagawa effective charge theory, we develop a model for electronic stopping power for an ion, which can be factorized into (i) a globally averaged effective charge taking into account effects of close and distant collisions by target electrons with the ion, and (ii) a local charge density dependent electronic stopping power for a proton. This phenomenological model is implemented into both molecular dynamics and Monte Carlo simulations. There is only one free parameter in the model, namely, the one electron radius r • s for unbound electrons. By fine tuning this parameter, it is shown that the model can work successfully for both boron and arsenic implants. We report that the results of the dopant profile simulation for both species are in excellent agreement with the experimental profiles measured by secondary-ion mass spectrometry (SIMS) over a wide range of energies and with different incident directions. We point out that the model has wide applicability, for it captures the correct physics of electronic stopping in ion implantation. This model also provides a good physically-based damping mechanism for molecular dynamics simulations in the electronic stopping power regime, as evidenced by the striking agreement of dopant profiles calculated in our molecular dynamics simulations with the SIMS data.

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Section: Bca Monte Carlo Simulation Resultsmentioning

confidence: 90%

Phenomenological electronic stopping-power model for molecular dynamics and Monte Carlo simulation of ion implantation into silicon

et al. 1996

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“…The BCA simulation is performed using the core of the BDoG code [37] under the following conditions: The incident energy of the helium atom E I = 100 eV. The Oen-Robinson model [48][49][50] is employed as a model of electron stopping power.…”

Section: Algorithm Of Bca-md-kmc Hybrid Methodsmentioning

confidence: 99%

Tungsten nanostructure growth by sputtering and redeposition in BCA-MD-KMC hybrid simulation

Ito,

Takayama,

Nakamura

2023

Mater. Res. Express

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The formation mechanism of fibrous tungsten nanostructures, fuzz, induced by helium plasma irradiation on tungsten materials has been investigated. We have developed a BCA-MD-KMC hybrid simulation, which solves the injection process of helium atoms by the Binary Collision Approximation (BCA) method, the diffusion process of helium atoms in tungsten materials by the Kinetic Monte-Carlo (KMC) method, and the deformation of tungsten materials due to helium bubbles by the Molecular Dynamics (MD) method. In addition, the model used to calculate the recoiling of tungsten atoms in BCA was improved to account for the reduced binding energy of tungsten atoms on rough surfaces. Using the hybrid simulation, the height of the nanostructures reached about 50 nm. The main mechanism of nanostructure growth was that sputtering and redeposition caused transport of tungsten atoms perpendicular to the surface. The present simulation was able to represent not only the dependence that the nanostructure height increases in proportion to the square root of the helium fluence, but also the existence of incubation fluence before the growth starts.

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“…A reasonable candidate for the dissipative viscous deceleration is Firsov relative-velocity damping 14 :…”

Section: General Theory Of Mesodynamicsmentioning

confidence: 99%

Mesodynamics with implicit degrees of freedom

Lin

Holian

Germann

et al. 2014

The Journal of Chemical Physics

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Mesoscale phenomena-involving a level of description between the finest atomistic scale and the macroscopic continuum-can be studied by a variation on the usual atomistic-level molecular dynamics (MD) simulation technique. In mesodynamics, the mass points, rather than being atoms, are mesoscopic in size, for instance representing the centers of mass of polycrystalline grains or molecules. In order to reproduce many of the overall features of fully atomistic MD, which is inherently more expensive, the equations of motion in mesodynamics must be derivable from an interaction potential that is faithful to the compressive equation of state, as well as to tensile de-cohesion that occurs along the boundaries of the mesoscale units. Moreover, mesodynamics differs from Newton's equations of motion in that dissipation-the exchange of energy between mesoparticles and their internal degrees of freedom (DoFs)-must be described, and so should the transfer of energy between the internal modes of neighboring mesoparticles. We present a formulation where energy transfer between the internal modes of a mesoparticle and its external center-of-mass DoFs occurs in the phase space of mesoparticle coordinates, rather than momenta, resulting in a Galilean invariant formulation that conserves total linear momentum and energy (including the energy internal to the mesoparticles). We show that this approach can be used to describe, in addition to mesoscale problems, conduction electrons in atomic-level simulations of metals, and we demonstrate applications of mesodynamics to shockwave propagation and thermal transport.

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The hidden mass of the universe

Cited by 10 publications

References 10 publications

Phenomenological electronic stopping-power model for molecular dynamics and Monte Carlo simulation of ion implantation into silicon

Phenomenological electronic stopping-power model for molecular dynamics and Monte Carlo simulation of ion implantation into silicon

Tungsten nanostructure growth by sputtering and redeposition in BCA-MD-KMC hybrid simulation

Mesodynamics with implicit degrees of freedom

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