A nonlinear theory of a complex crystalline lattice composed of two mutually penetrating sub-lattices typical of semiconductive crystals, such as diamond, silicon, germanium, etc., is proposed. Special attention is attracted to short-range order effects responsible for cardinal structural changes, including the generation of defects and a new phase, and to so called reconstructive transitions, i.e. changes of crystal symmetry class. Solutions of deformation equations, which describe a motion of periodical waves and kink ? and soliton ? like defects of microstructure, are found. Their mutual transitions for certain tensions and velocities of travel are considered.
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