Predicting temp. at which defects will set in

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Hi,

I am calculating surface energies for different kinds of defects in a bulk solid (e.g. twins, anti-phase boundaries, etc.) Let's say I get something like (just making this up) 1.0 meV/Angstrom^2. How would I calculate the temperature at which an appreciable number of said defect would be present in the sample? Classically, you have something like k_B T energy available per mode. But I get confused thinking about what might constitute a mode when talking about surface defects forming in a bulk crystal.

Thanks for suggestions,
Sam
 
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I'm not aware of any statistical mechanical model that gives "equilibrium" number of "extended" defects (anything different than point defects) at a given temperature. Even the word "equilibrium" may not be appropriate here.
 
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