Electron or ion irradiation-induced phase-change mechanism between amorphous and crystalline state

Electron or ion irradiation-induced phase change between the amorphous and crystalline state is a long-standing and puzzling problem. In this paper, the energy dissipation based on irradiation-assisted atomic rearrangement was found to be a crucial mechanism for irradiation-induced crystallization. The occurrence of crystallization needs to meet two criteria: (i) that the irradiation enhances the atomic order and (ii) that the crystalline nuclei are structurally stable. This work provides a general answer as to why the external energy deposition into an amorphous system could cause the lowering of free energy and trigger the athermal transformation from the amorphous to the crystalline state. Based on the energy dissipation assumption and the modified Lindemann model, the underlying relationship between irradiation-induced crystallization and amorphization was clarified.