First principles investigation of interaction between impurity atom (Si, Ge, Sn) and carbon atom in diamond-like carbon system

►Distortion energy after bond angle distortion was decreased comparing with CC unit. ►The weak covalent bond was formed between impurity atoms and corner carbon atoms. ►Observed electron transfer behavior affected the strength and directionality of bond. ►Reduction of strength and directionality of bond contributed to small energy change.