RUDERMAN-KITTEL-LIKE INTERACTION OF ELECTRIC DIPOLES IN SYSTEMS WITH CARRIERS

The energy of indirect interaction of off-center ions via conduction electrons is derived. The calculations are carried out for ions described by double-well potentials with the axis along a cubic axis of the lattice. Tunnel motion of ions is taken into account. It was shown that the obtained electric dipole-dipole interaction V(dd) depends on the values of the ion electric dipole moment, electron wave vector on the Fermi surface, and is an alternating sign function of the distance between the dipoles. The form of this function for the main part of V(dd) looks like the well-known Ruderman-Kittel interaction of magnetic dipoles. Estimations show that the value of interaction is comparable with the conventional electric dipole-dipole interaction.