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The properties of regions swept by a moving dislocation in silicon crystals are experimentally studied. The peculiarities of forming traces of various types behind dislocations observed by electron microscopy and chemical etching are investigated. These traces are found to arise as result of point defect redistribution by moving dislocations and change in their structural state in a volume swept by a dislocation. It is shown that the processes mentioned enable the slip plane to assume properties of a specific two‐dimensional defect responsible for the appearance of the new mechanism of a charge carrier mobility anisotropy in the plastically deformed crystals.

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The temperature dependence of the Vickers hardness is measured on the basal (0001) plane of single crystal α‐Al2O3 (sapphire) from room temperature to 1273 K. The plastic zone surrounding the indents is investigated using selective chemical polishing and etching, optical microscopy, and transmission electron microscopy (TEM). Indentation was accompanied by three competitive damage processes: fracture, twinning, and dislocation plasticity. At room temperature, cracking predominates, and the presence of dislocations and/or twins could be revealed only by TEM. At intermediate temperatures (673 to 1073 K), extensive rhombohedral twinning is observed, while at higher temperatures, prismatic slip bands on {1120} dominates the microstructure. TEM observations reveal that the dislocation substructure at the vicinity of the indents consists of fairly straight dislocations lying in basal and/or prism planes and aligned along the 〈1010〉 and 〈1120〉 directions. The details of the glide dissociation of perfect 〈1010〉 screw dislocations into three collinear 1/3 〈1010〉 partials on the prism plane, the mechanism of the microplasticity of sapphire single crystals, and details of the Peierls potential for α‐Al2O3 are discussed.