  A general mechanism by which orbital ordering, coupled to Peierls-like
lattice distortions, can induce an electronic switchable polarization is
discussed within a model Hamiltonian approach in the context of the modern
theory of polarization. By using a Berry-phase approach, a clear picture
emerges in terms of Wannier-function centers and orbital occupancies. The
proposed mechanism may apply to oxide spinels whose electronic structure has
effective one-dimensional character, such as CdV$_2$O$_4$, recently proposed to
display multiferroic behaviour.
