Abstract
In this work a periodic crystal with point defects is described in the framework of linear-response theory for broken-symmetry states using correlation functions and Zwanzig-Mori equations. The main results are microscopic expressions for the elastic constants and for the coarse-grained density, point-defect density, and displacement field, which are valid in real crystals, where vacancies and interstitials are present. The coarse-grained density field differs from the small wave-vector limit of the microscopic density. In the long-wavelength limit, we recover the phenomenological description of elasticity theory including the defect density.
- Received 8 December 2009
DOI:https://doi.org/10.1103/PhysRevB.81.134110
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