  We study models compactified on S^1/Z_2 with bulk and brane matter fields
charged under U(1) gauge symmetry. We calculate the FI-terms and show by
minimizing the resulting potential that supersymmetry or gauge symmetry is
spontaneously broken if the sum of the charges does not vanish. Even if this
sum vanishes, there could be an instability as a consequence of localized
FI-terms. This leads to a spontaneous localization of charged bulk fields on
respective branes.
