Molecular dynamics simulation of radiation damage in CaCd6 quasicrystal cubic approximant up to 10 keV

Abstract

Due to the peculiar nature of the atomic order in quasicrystals, examining phase transitions in this class of materials is of particular interest. Energetic particle irradiation can provide a way to modify the structure locally in a quasicrystal. To examine irradiation-induced phase transitions in quasicrystals on the atomic scale, we have carried out molecular dynamics simulations of collision cascades in CaCd 6 quasicrystal cubic approximant with energies up to 10 keV at 0 and 300 K. The results show that the threshold energies depend surprisingly strongly on the local coordination environments. The energy dependence of stable defect formation exhibits a power-law dependence on cascade energy, and surviving defects are dominated by Cd interstitials and vacancies. Only a modest effect of temperature is observed on defect survival, while irradiation temperature increases lead to a slight increase in the average size of both vacancy clusters and interstitial clusters.

Ab initio computer simulations of non-equilibrium radiation-induced cascades in amorphous Ge2Sb2Te5

“…The time dependence of the kinetic energy of the Te PKA and the maximum kinetic energy of Ge, Sb and the rest of the Te atoms among all the atoms contained in the simulation box, shown in figure 3 for the 200 eV thermal-spike simulation, provides further details for the short-lived nonequilibrium cascade and it can be used in order to convey a sense of the strength, timing and duration of the interactions involved in the simulated cascade [12]. The PKA lost 90% of its initial energy within the first 0.14 ps of the simulation, while the maximum kinetic energy for all atomic species in the modelled system is negligible after 0.35 ps and, in practice, the radiation-damage cascade event is complete.…”

“…The final stage of the ion-irradiation process almost always involves many-body collisions between atoms within the glass network. Molecular dynamics (MD) is a computational method that is naturally suited for simulating many-body collisions [10][11][12][13][14][15]. It is noted that classical MD simulations in amorphous Ge 2 Sb 2 Te 5 have been hampered by the lack of a force field able to describe the complex bonding interactions present in this type of material.…”

Molecular Dynamics

“…A variable stepsize is only used where one expects extreme changes in particle velocities over the course of a simulation (see e.g [75,390]. for examples arising in radiation damage cascades).…”

Quasilattice-Conserved Optimization of the Atomic Structure of Decagonal Ael-Co-Ni Quasicrystals

“…On the other hand, first-principles calculations 6 , together with inter-atomic potential methods [8][9][10] , have also been applied to the quandary. Although theoretical calculations based on first-principles and empirical potentials can offer some insights into the atomic structure, it is far from conclusive for the detailed atomic positions of quasicrystals because of the complicated structure in addition to potential expensive computational efforts.…”