Abstract:
The model for a vacancy in a lattice consists of a linear chain of the atoms, which
contains one vacant site, together with a substrate potential. For this model the diffusion
coefficient of vacancy is studied on the basis of the Kubo's expression for the
transport coefficient. In deriving one a lattice distortion around the vacancy and massdifference
scattering are taken into account. Two mechanisms of the transition the
atom in the neighbouring vacant site is considered: the Orbach-type process at high
temperatures which lead to the Arrhenius-type expression (the classical picture) and
the tunnel transition at low temperatures. The phonon scattering is described by means
of the $t$-matrix and Green function method.
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