Ab initio mechanical response: internal friction and structure of divacancies in silicon

This letter introduces ab initio study of the full activation-volume tensor of crystalline defects as a means to make contact with mechanical response experiments. We present a theoretical framework for prediction of the internal friction associated with divacancy defects and give the first ab initio value for this quantity in silicon. Finally, making connection with defect alignment studies, we give the first unambiguous resolution of the debate surrounding ab initio verification of the ground-state structure of the defect.