  The spectrum of a massless bulk scalar field \Phi, with a possible
interaction term of the form -\xi R \Phi^{2}, is investigated in the case of
RS-geometry [1]. We show that the zero mode for \xi=0, turns into a tachyon
mode, in the case of a nonzero negative value of \xi (\xi<0). As we see, the
existence of the tachyon mode destabilizes the \Phi=0 vacuum, against a new
stable vacuum with nonzero \Phi near the brane, and zero in the bulk. By using
this result, we can construct a simple model for the gauge field localization,
according to the philosophy of Dvali and Shifman (Higgs phase on the brane,
confinement in the bulk).
