  A thermoelectric effect of the noncentrosymmetric electron-phonon coupled
system is proposed, in which a temperature difference between electrons and
phonons, instead of a spatial temperature gradient, induces an electric
current. This is a realization of Seebeck ratchet in solids with the asymmetric
energy dispersion of electrons, and the dynamical phonons act as the
fluctuation of the scalar potential and induce the dc current. Possible
realizations of this mechanism are also discussed.
