  The theory of the dislocation motion in the periodic potential relief of the
crystal lattice (the Peierls-Nabarro barriers) is reviewed. On the basis of the
kink mechanism the temperature dependence of the flow stress is described for a
wide class of materials. The theory of quantum mechanical dislocation
tunnelling through the Peierls-Nabarro barriers is extended and compared with
experimental data on the plasticity of alkali halides, BCC and HCP metals at
low temperatures. The behavior of the flow stress at the range of athermic
anomalies is modeled by changing the mechanism of the dislocation motion from
the thermally activated hopping over the barriers to the quantum tunnelling
through them. Some results of previous calculations are represented in a more
explicit convenient for applications form. The pronounced effect of the
switching between the normal and the superconducting states on the flow stress
of metals is explained on the basis of the change in the dissipative properties
of the electron subsystem affecting the dislocation motion.
