Theoretical study of the channeling effect in the electronic stopping power of silicon carbide nanocrystal for low-energy protons and helium ions

Mao, Fei; Zhang, Chao; Zhang, Feng-Shou

doi:10.1016/j.nimb.2014.09.035

Cited by 9 publications

(3 citation statements)

References 53 publications

(62 reference statements)

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“…However, the utilization of HIM in thin materials has not yet been systematically investigated. Firstly, the crystalline structure of the material is always ignored, although the channel effect is reported in some simulation work [10] or imaging experiments [11,12]. It is exactly proper to ignore the effect of crystalline structure on the milling processes for polycrystalline bulk sample.…”

Section: Introductionmentioning

confidence: 99%

Nano-patterning of a monolayer molybdenum disulfide with sub-nanometer helium ion beam: considering its shape, size and damage

Deng¹,

Wang²,

Qiu³

et al. 2020

Nanotechnology

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We have studied nano-patterning of a two-dimensional (2D) material with an ultrafine helium ion beam considering shape-, size- and damage-control. The study reveals that the crystalline structure plays an important role in shape-control. Instead of commonly circular-shaped nanopores, spot irradiation onto a single layer of molybdenum disulfide (MoS2) gives rise to a rhombus-shaped nanopore, which is well explained by the sub-rhombus crystalline structure of MoS2. Helium ion beams also show promising capability to precisely control size using a delivered dose. However, the size of the nanopores is not linear with the delivered dose, due to the Gaussian distributed intensity profile of the helium ion beam. The intensity profiles are further estimated by considering aperture size, those results could be taken as a significant reference for size-control. In addition, we clarify that most of the damage is a result of re-deposition, thus controlling re-deposition might be a useful way to alleviate the damage.

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Section: Introductionmentioning

confidence: 99%

Nano-patterning of a monolayer molybdenum disulfide with sub-nanometer helium ion beam: considering its shape, size and damage

Deng¹,

Wang²,

Qiu³

et al. 2020

Nanotechnology

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“…It should be noted that the ESP obtained from SRIM data is the average result for different incident directions with various impact parameters, including the channeling and offchanneling conditions. In recent years, the SRIM data has been employed as a standard reference value, and the TDDFT results of ESP have been compared with the SRIM data in many theoretical research to judge whether their data are reliable or not [49,50]. In general, the calculated results follow the qualitative trend of SRIM data, indicating that these results are reliable.…”

Section: Inversion Of Espmentioning

confidence: 99%

Crossover of energy deposition and semi-stable chemical bonding in the nonadiabatic dynamics of GaN under proton irradiation

Deng

Feng

2023

J. Phys.: Condens. Matter

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Understanding the ion-solid interactions of charged particles in materials facilitates the development of ion beam irradiation techniques. Combining Ehrenfest dynamics and time-dependent density-functional theory (ED-TDDFT), we investigated the electronic stopping power (ESP) of an energetic proton in GaN crystal and studied the ultrafast dynamic interaction between the proton and target atoms during the nonadiabatic process. We found a crossover phenomenon of ESP at 0.36 a.u. along the <100> and <110> channels, which is interpreted by the charge transfer between the host material and the projectile and the stopping force exerted on the proton. At velocities of 0.2 and 1.7 a.u., we demonstrated that the reversal of the average number of charge transfer and the average axial force resulted in the reversed energy deposition rate and ESP in the corresponding channel. Further analysis of the evolution of non-adiabatic electronic states revealed the existence of the transient and semi-stable N-H chemical bonding during irradiation process, which is introduced by the electron clouds overlap of N sp3 hybridization and the s orbitals of the proton. These results provide meaningful information for the interactions between energetic ions with matter.

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“…Relatively recently, time-dependent density functional theory (TDDFT) has been used to determine the electronic stopping for a number of projectile-target combinations. [24][25][26][27][28][29][30] Unlike the free electron gas-based models, 31 TDDFT explicitly takes into account the effects of inhomogeneity in electron density due to the underlying lattice structure, band structure, 32 band gap, 14 and core-state excitations. [33][34][35] Furthermore, the charge state of the projectile need not be imposed in TDDFT calculations, but rather is an outcome of the method itself.…”

Section: Introductionmentioning

confidence: 99%

Heavy ion ranges from first-principles electron dynamics

2019

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The effects of incident energetic particles, and the modification of materials under irradiation, are governed by the mechanisms of energy losses of ions in matter. The complex processes affecting projectiles spanning many orders of magnitude in energy depend on both ion and electron interactions. Developing multi-scale modeling methods that correctly capture the relevant processes is crucial for predicting radiation effects in diverse conditions. In this work, we obtain channeling ion ranges for tungsten, a prototypical heavy ion, by explicitly simulating ion trajectories with a method that takes into account both the nuclear and the electronic stopping power. The electronic stopping power of self-ion irradiated tungsten is obtained from first-principles timedependent density functional theory (TDDFT). Although the TDDFT calculations predict a lower stopping power than SRIM by a factor of three, our result shows very good agreement in a direct comparison with ion range experiments. These results demonstrate the validity of the TDDFT method for determining electronic energy losses of heavy projectiles, and in turn its viability for the study of radiation damage.npj Computational Materials (2019) 5:43 ; https://doi.

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Theoretical study of the channeling effect in the electronic stopping power of silicon carbide nanocrystal for low-energy protons and helium ions

Cited by 9 publications

References 53 publications

Nano-patterning of a monolayer molybdenum disulfide with sub-nanometer helium ion beam: considering its shape, size and damage

Nano-patterning of a monolayer molybdenum disulfide with sub-nanometer helium ion beam: considering its shape, size and damage

Crossover of energy deposition and semi-stable chemical bonding in the nonadiabatic dynamics of GaN under proton irradiation

Heavy ion ranges from first-principles electron dynamics

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