The plasticity of undoped GaAs is studied between 528 and 813 K at low shear strain rate (\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop \gamma \limits^. $\end{document} ≈︁ ≈︁4 × 10−5s−1) by uniaxial compression along [123]in order to favour simple glide. The double deformation experiments are completed by stress relaxation tests and TEM observations. The anal‐ysis of the results from the formalism of thermal activation shows that two temperature ranges can be distinguished: below 650 K the plastic deformation seems to be controlled by the mobility of screw dislocations (Peierls mechanism) with an activation energy decreasing from 2.5 (at 650 K) to 2.0 eV (at 528 K), above 650 K the involved mechanisms are more complex; they are related to the dislocation substructure (edge dipoles and multipoles) generated by the predeformation.

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