  Massless fermions on scalar domain walls are considered. Two walls are
established, corresponding to 5-dimensional static spacetime asymptotically
Anti de-Sitter, differentiated by the symmetry around the wall, and in each
case massless chiral fermions are coupled to the wall by a Yukawa term. We
identify a normalizable state associated to the migration of fermions toward
the edge of the wall. This effect is generated by the competition between the
Yukawa interaction and the gravitational repulsion on the matter fields, and it
is independent of the $Z_2$ symmetry of the wall.
