We study the localization of the electronic wave functions of quasiper
iodic superlattices in an electric field. Although the electric field
localizes the states on average, an exotic behavior appears at certain
values of the electric field applied, for which the localization leng
th of the states presents local maxima, and the states become more ext
ended. We explain this effect by considering that the field limits the
region of the system reachable by the electron. (C) 1997 Elsevier Sci
ence B.V.