  Partial electron localization in a finite-size superlattice placed in an
electric field is considered. The role of electric field in forming of
quasilocalized states is investigated. A quantitative criterion for the degree
of partial localization is suggested based on analysis of maximal probability
density of finding an electron at a given point. It is found that with increase
in the electric field the degree of localization does not increase
monotonically. Furthermore, the localization is affected stronger by the
amplitude of superlattice potential than by the electric field.
