Point Defects and Material Response

This chapter is the first in a series that will make the case that many of the important features of real materials are dictated in large measure by the presence of defects. Whether one s interest is the electronic and optical behavior of semiconductors or the creep resistance of alloys at high temperatures, it is largely the nature of the defects that populate the material that will determine both its subsequent temporal evolution and response to external stimuli of all sorts (e.g. stresses, electric fields, etc.). Eor the most part, we will not undertake an analysis of the widespread electronic implications of such defects. Rather, our primary charter will be to investigate the ways in which point, tine and wall defects impact the thermomechanical properties of materials. 

The condensed matter physicist has traditionally built up a picture of a solid which is measured against the perfect crystal of infinite extent. The structure is imagined as a monotonous continuation of perfectly repeating units. Ear reaching theorems such as that of Bloch emanate from this periodicity and allow for the determination of the types of insights we constructed for the vibrational 

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