Energetics and electronic levels

1 Intrinsic point defects 9.1.1 Energetics and electronic levels 

Vacancies are quite common in many crystals, both in close-packed metallic structures as well as in open covalent structures. The creation of a vacancy costs some energy, due to the breaking of bonds, which is called the formation energy This is defined as the energy of the crystal containing a vacancy, that is, one atom fewer than the ideal crystal which has N atoms, denoted as — 1), plus the 

Interstitial atoms are extra atoms that exist in the crystal at positions that do not coincide with regular crystalline sites. These defects are common in crystals with open structures since in close-packed crystals there simply is not enough room to accommodate extra atoms it costs a great amount of energy to squeeze an extra atom into a close-packed crystal. The energy to create an interstitial, its formation 

9 Defects I point defects Ideal Vacancy Relaxed Vacancy 

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