First-principles study of the diffusion mechanisms of the self-interstitial in germanium

The self- interstitial in germanium can assume multiple configurations depending on the temperature and charge state. Here, we employ a first- principles density functional method to investigate the diffusion mechanisms of this defect. The energy barriers associated with the transformation between different structures are determined by the climbing nudged elastic band method, as a function of the charge state. The relation between the thermodynamic properties of the self- interstitial and the temperature evolution of electron radiation damage in germanium are discussed.