Finding the concentrations of vacancies and interstitials

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SUMMARY

The discussion focuses on calculating the concentrations of vacancies and interstitials in a two-dimensional ionic crystal with a primitive hexagonal lattice at 300 K. The energy required to create a Frenkel defect pair is 10 eV, while the Schottky defect formation energy is 8 eV. Using the formula n/N = e^(-Edef/kbT), it is established that the equilibrium concentration of these defects at room temperature is effectively zero, despite their theoretical presence in the crystal structure.

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Tom Weaver
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Consider a two-dimensional ionic crystal with a primitive hexagonal lattice. The energy needed to create a Frenkel defect pair is 10eV, and Schottky defect formation costs 8eV.
Calculate the concentration of vacancies and interstitials in the crystal at 300 K, assuming that all defects are intrinsic.

n/N=e-(Edef/kbT)
Where: n = number of defects
N = number of atoms in the crystal
Edef = defect creation energy
kb = Boltzmann's constant
T = temperature

I've tried using 10eV and 8eV as the defect creation energy however this equals to an answer smaller than *10-100, unsure how to progress.

Thanks in advance!
 
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That is correct. The equilibrium concentration for those defects at room temperature is effectively zero.

Why do we still have those defects in crystals?
 

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