Accelerator Laboratory, University of Helsinki, P.O. Box 43, 00014 Helsinki, Finland.
J Chem Phys. 2013 Jun 21;138(23):234505. doi: 10.1063/1.4811183.
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 CaCd6 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.
由于准晶体中原子排列的特殊性，研究这类材料中的相变具有特别的意义。高能粒子辐照可以在局部对准晶体的结构进行修改。为了在原子尺度上研究准晶体中的辐照诱导相变，我们对 CaCd6 准晶立方近晶相进行了能量高达 10keV 的 0K 和 300K 下的碰撞级联的分子动力学模拟。结果表明，阈能出人意料地强烈依赖于局部配位环境。稳定缺陷形成的能量依赖性表现出与级联能量的幂律关系，而幸存的缺陷主要由 Cd 间隙原子和空位组成。缺陷的存活率仅受到温度的适度影响，而辐照温度的升高会导致空位团簇和间隙团簇的平均尺寸略有增加。
