Insights into different stages of formation of swift heavy ion tracks

Rymzhanov, R.A.; Medvedev, Nikita; O’Connell, J.H.; Skuratov, V.A.; Vuuren, A. Janse van; Горбунов, С.; Волков, А. Е.

doi:10.1016/j.nimb.2020.04.005

Cited by 19 publications

(28 citation statements)

References 64 publications

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“…We see that in the case of an SHI impact, almost all the energy is transferred to atoms already within sub-100 fs timescales, also in agreement with previous studies. [17,28] The spatial distribution of the energy transfer rate from the electronic to the atomic system is shown in Figure 4. The radial distribution decays exponentially, but its shape is not constant in time.…”

Section: Swift Heavy Ion Irradiation Of Al 2 Omentioning

confidence: 99%

“…Figure 6 shows a comparison of the results within the first 100 fs of irradiation of Al 2 O 3 with 30 MeV Xe ion simulated with the proposed TREKIS-4 approach versus previous results of combined MC output data on atomic Figure 6. Comparison between MD atomic snapshots of Al 2 O 3 within 100 fs after irradiation with 30 MeV Xe ion, calculated with the current approach (top panels: TREKIS-4) versus that calculated with TREKIS-3 + LAMMPS approach (bottom panels), [17,28] which uses MC output data as an instantaneous input for MD simulation.…”

Section: Appendixmentioning

confidence: 99%

“…For simulation of localized ion tracks, the borders of the simulation box are cooled with the Berendsen thermostat. [ 17 ] This allows mimicking the realistic scenario of a track embedded in an unirradiated target using a finite‐size supercell. For laser pulse simulations, an entire supercell may be homogeneously cooled at a slower rate, or no cooling at all may be used.…”

Section: Modelmentioning

confidence: 99%

“…Upon relaxation of the electronic system, the target atoms react to the energy transferred at pico‐ to nanosecond timescales. [ 17,18 ] Finally, after cooling of the atomic system, the target may be left in a structurally modified state, observable experimentally. [ 1,9 ]…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Modeling Time‐Resolved Kinetics in Solids Induced by Extreme Electronic Excitation

Medvedev

Akhmetov

Rymzhanov

et al. 2022

Advcd Theory and Sims

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The authors present a concurrent Monte Carlo (MC)-molecular dynamics (MD) approach to modeling matter response to excitation of its electronic system at nanometric scales. The two methods are combined on-the-fly at each time step in one code, TREKIS-4. The MC model describes the arrival of irradiation (a photon, an electron, or a fast ion). It traces induced cascades of secondary electrons and holes, and their energy exchange with atoms due to scattering. The excited atomic system is simulated with an MD model. An efficient way is proposed to account for nonthermal effects in the electron-atom energy transfer in covalent materials via the conversion of the potential energy of the electronic ensemble into the kinetic energy of atoms. Such a combined MC-MD approach enables a time-resolved tracing of the excitation kinetics of both, the electronic and atomic systems, and their simultaneous response to a deposited dose. As a proof-of-principle, it is shown that the proposed method describes atomic dynamics after X-ray irradiation in good agreement with tight-binding MD. The model also allows gaining insights into the atomic system behavior during the energy deposition from a nonequilibrium electronic system excited by an ion impact.

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Section: Swift Heavy Ion Irradiation Of Al 2 Omentioning

confidence: 99%

Section: Appendixmentioning

confidence: 99%

Section: Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Modeling Time‐Resolved Kinetics in Solids Induced by Extreme Electronic Excitation

Medvedev

Akhmetov

Rymzhanov

et al. 2022

Advcd Theory and Sims

Self Cite

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“…While most first-principles approaches 17,18 are still limited to studying femtosecond dynamics, Monte Carlo 19,20 simulations describing the initial kinetics of the electrons and holes can reach longer time and spatial scales. Recently, these have been combined with molecular dynamics (MD) simulations 21 . Such approaches are promising, but the number of cases studied extensively is still low.…”

Section: Introductionmentioning

confidence: 99%

Insights into nanoparticle shape transformation by energetic ions using atomistic simulations

Leino¹,

Jantunen²,

Djurabekova³

2022

Preprint

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The shape of metal nanoparticles embedded in dielectric matrices influences the optical properties of the composite material. Swift heavy ion irradiation can induce a controllable shape transformation in gold and other metals embedded in amorphous silicon dioxide, where the particles elongate along the direction of the ion beam. The details of this transformation are not fully understood, but it is presumably related to nanometer-scale phase transitions induced by individual ion impacts. The phenomenon has been reproduced using atomistic simulations, although the time scale limitations and the lack of accurate interatomic models within the metal-silica interface lead unavoidably to severe simplifications.We improve the realism in the simulations with an accurate model for surface adhesion between gold and silica and by simulating the processes in the matrix between impacts. The simulations with correct adhesion show that the nanoparticles can grow in aspect ratio in the molten state even after silicon dioxide solidifies. Moreover, we demonstrate the active role of the matrix: without explicitly modeling processes in the matrix between impacts, the elongation is limited and does not reach significant aspect ratios seen in experiments. These results significantly improve the theoretical understanding of processes developing in embedded nanoparticles under swift heavy ion irradiation. The knowledge brings forward the ion beam technology as a precise tool for shaping of embedded nanostructures for various optical applications.

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Examining Different Regimes of Ionization‐Induced Damage in GaN Through Atomistic Simulations

Sequeira

Djurabekova

Nordlund

et al. 2022

Small

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The widespread adoption of gGaN in radiation‐hard semiconductor devices relies on a comprehensive understanding of its response to strongly ionizing radiation. Despite being widely acclaimed for its high radiation resistance, the exact effects induced by ionization are still hard to predict due to the complex phase‐transition diagrams and defect creation‐annihilation dynamics associated with group‐III nitrides. Here, the Two‐Temperature Model, Molecular Dynamics simulations and Transmission Electron Microscopy, are employed to study the interaction of Swift Heavy Ions with GaN at the atomic level. The simulations reveal a high propensity of GaN to recrystallize the region melted by the impinging ion leading to high thresholds for permanent track formation. Although the effect exists in all studied electronic energy loss regimes, its efficiency is reduced with increasing electronic energy loss, in particular when there is dissociation of the material and subsequent formation of N2 bubbles. The recrystallization is also hampered near the surface where voids and pits are prominent. The exceptional agreement between the simulated and experimental results establishes the applicability of the model to examine the entire electronic energy loss spectrum. Furthermore, the model supports an empirical relation between the interaction cross sections (namely for melting and amorphization) and the electronic energy loss.

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Insights into different stages of formation of swift heavy ion tracks

Cited by 19 publications

References 64 publications

Modeling Time‐Resolved Kinetics in Solids Induced by Extreme Electronic Excitation

Modeling Time‐Resolved Kinetics in Solids Induced by Extreme Electronic Excitation

Insights into nanoparticle shape transformation by energetic ions using atomistic simulations

Examining Different Regimes of Ionization‐Induced Damage in GaN Through Atomistic Simulations

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