  The peculiarities of superstructural transition (2x4) -> (3x1(6)) on the
GaAs(001) surface were studied by the RHEED method in the conditions initiated
by a sharp change of the arsenic flux. The specular beam intensities RHEED
picture dependences on time were obtained during the transition. The
measurement results were analyzed within the JMAK (Johnson - Melh - Avrami -
Kolmogorov) kinetic model. It was established that the process of structural
rearrangement proceeds in two stages and it is realized through the state of
intermediate disordering, domains with different reconstructions being
coexistent on the surface. The activation energies and phase transition
velocities were determined for each of the stages. The procedure for precise
determination of GaAs(001) surface temperature using the features of the
a(2x4)->DO transition process kinetic was proposed. The results of this work
allow us to broaden our understanding of the reconstruction transitions
mechanisms. This information has a key (fundamental and applied) nature for the
technologies of epitaxial growth of multilayer heterostructures, where the
interface planarity and the sharpness of composition profile are of particular
importance.

Materials Science