Trajectory-dependent electronic excitations by light and heavy ions around and below the Bohr velocity

Lohmann, Svenja; Holeňák, Radek; Primetzhofer, Daniel

doi:10.1103/physreva.102.062803

Cited by 26 publications

(15 citation statements)

References 54 publications

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“…The stopping powers found for the off-center <001> trajectories are a bit higher than those for the center, and this discrepancy increases with the projectile velocity. Our results for the center channel and those of [36] are in good agreement with the state-of-the-art experimental results of [11] for the <001> center channel. This gives us confidence in the reliability of the electronic stopping powers calculated from TDDFT despite the fact that our stoppings are 2 to 3 times smaller than SRIM stopping powers.…”

Section: Electronic Stopping Power Calculationssupporting

confidence: 89%

“…1, the electronic stopping powers of initially neutral Si projectiles into bulk Si along the center <001> channel and the off-center <001> channel (1/2) are shown with respect to the velocity of the projectile. The results of TDDFT calculations from [36], experimental results [11] and SRIM results are also shown for comparison. Energy (keV)…”

Section: Electronic Stopping Power Calculationsmentioning

confidence: 99%

“…Despite the major breakthrough that this model represented, it suffers from certain limitations. Firstly, the electronic density is considered constant in the entire model The electronic stopping power thus cannot be crystal direction-dependent as it was confirmed to be by recent experiments [11] and Time Dependent Density Functional Theory (TDDFT) calculations [12]. Secondly, a recent paper pointed out [13] the large uncertainties in the choice of values for some parameters of the model, due to the lack of the-oretical or experimental data in the literature.…”

Section: Introductionmentioning

confidence: 97%

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Integration of electronic effects into molecular dynamics simulations of collision cascades in silicon from first-principles calculations

et al. 2021

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The inclusion of sophisticated density-dependent electronic stopping and electron-phonon coupling calculated with first-principles methods into molecular dynamics simulations of collision cascades has recently become possible thanks to the development of the so-called EPH (for Electron-PHonon) model. This work aims at employing the EPH model in molecular dynamics simulations of collision cascades in Si. In this context, the electronic stopping power is investigated in Si at low energies with Ehrenfest Dynamics calculations. Also, the parametrization of the EPH model for Si, from firstprinciples Ehrenfest Dynamics simulations to actual molecular dynamics simulations of collision cascades, is performed and detailed. We demonstrate that the EPH model is able to reproduce very closely the density-dependent features of the energy lost to electrons obtained with ab initio calculations. Molecular dynamics collision cascade simulations results obtained in Si using the EPH model and the simpler but widely employed Two Temperature Model (TTM) are compared, showing important discrepancies in the collision cascades results obtained depending on the model employed.

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Section: Electronic Stopping Power Calculationssupporting

confidence: 89%

Section: Electronic Stopping Power Calculationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

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Integration of electronic effects into molecular dynamics simulations of collision cascades in silicon from first-principles calculations

et al. 2021

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“…In consequence, even for light ions, theoretical predictions by static theories can be inaccurate, 7 and computationally expensive calculations taking the dynamics of the interaction into account are necessary for an accurate description of experimental observations. 8,9 Such predictions of the stopping power of a material for, in particular, heavy ions are essential for predicting particle range in ion implantation and energy deposition in irradiation. In Ion Beam Analysis (IBA), 10 where the energy loss of detected ions is the common observable quantity, the specific energy loss permits to obtain accurate depth perception.…”

Section: Introductionmentioning

confidence: 99%

Assessing electronic energy loss of heavy ions detected in reflection geometry

Kantre

Moro

Paneta

et al. 2021

Surface & Interface Analysis

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We study energy loss spectra of bromine ions scattered from silver thin films in the energy range of 4 to 36 MeV in forward reflection geometry. The different contributions to the energy loss are analyzed by complementary Monte Carlo simulations.We assess the dependence of the scattering yield and nuclear and electronic losses on the penetration depth of detected ions. For scattering from larger depth, we observe decreased elastic losses and increased trajectory length in comparison with predictions from single scattering, with increasing effects for lower energies. To investigate the entanglement of energy loss and depth information, electronic stopping cross sections are deduced from the experimental spectra by two different approaches: (a) assuming a single scattering model and (b) making use of Monte Carlo simulations. The data obtained from the two approaches are compared, and we assess the relative contributions from nuclear stopping and from the effect of multiple scattering on trajectory length. Results of both methods are discussed in the context of composition depth profiling and compared with data from literature and with Stopping and Range of Ions in Matter (SRIM) predictions resulting in good agreement.

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“…This dependency is the main topic of this manuscript. Atomistic simulations are in a unique position to explore this dependency in a systematic way, beyond what models [10] and the most accurate state-of-the-art experiments can do [11].…”

Section: Introductionmentioning

confidence: 99%

Directional dependency of electronic stopping in nickel, projectile’s excited charge state and momentum transfer

2021

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We studied the directional dependency of electronic stopping power of swift light ions in nickel using real-time time-dependent density functional theory. We report a variation of electronic stopping for moving ions as the projectile probes different electronic densities of the host material. These results show that while the predicted magnitude stays in reasonable agreement with experiment, for $$v > 2$$ v > 2 . a.u. simulating only low index crystallographic directions is not enough to sample the experimental average values. The ab initio simulations give us access to microscopic quantities, such as non-adiabatic forces, momentum transfer and transient excited state charges of the projectile and host ions, which are not available through other methods. We report these quantities for the first time.

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Trajectory-dependent electronic excitations by light and heavy ions around and below the Bohr velocity

Abstract: We present experiments demonstrating trajectory-dependent electronic excitations at low ion velocities, where ions are expected to primarily interact with delocalized valence electrons. The energy loss of H

Cited by 26 publications

References 54 publications

Integration of electronic effects into molecular dynamics simulations of collision cascades in silicon from first-principles calculations

Integration of electronic effects into molecular dynamics simulations of collision cascades in silicon from first-principles calculations

Assessing electronic energy loss of heavy ions detected in reflection geometry

Directional dependency of electronic stopping in nickel, projectile’s excited charge state and momentum transfer

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