Molecular dynamics study of structural damage in amorphous silica induced by swift heavy-ion radiation

ABSTRACT

In this paper, the radiation defects induced by the swift heavy ions and the recoil atoms in amorphous SiO₂ were studied. The energy of recoil atoms induced by the incident Au ions in SiO₂ was calculated by using Monte Carlo method. Results show that the average energies of recoils reach the maximum (200 eV for Si and 130 eV for O, respectively) when the incident energy of Au ion is 100 MeV. Using Tersoff/zbl potential with the newly built parameters, the defects formation processes in SiO₂ induced by the recoils were studied by using molecular dynamics method. The displacement threshold energies (E_d) for Si and O atoms are found to be 33.5 and 16.3 eV, respectively. Several types of under- and over-coordinated Si and O defects were analyzed. The results demonstrate that Si₃, Si₅, and O₁ are the mainly defects in SiO₂ after radiation. Besides, the size of cylindrical damage region produced by a single recoil atom was calculated. The calculation shows that the depth and the radius are up to 2.0 and 1.4 nm when the energy of recoils is 200 eV. Finally, it is estimated that the Au ion would induce a defected track with a diameter of 4 nm in SiO₂.

KEYWORDS:

• Damage
• defects
• radiation
• tracks

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant number 11175271], [grant number 11402221].