  Current-voltage characteristics and $P-E$ loops are simulated in
SrRuO$_{3}$/BaTiO$_{3}$/Pt tunneling junctions with interfacial dead layer. The
unswitchable interfacial polarization is coupled with the screen charge and the
barrier polarization self-consistently within the Thomas-Fermi model and the
Landau-Devonshire theory. The shift of P-E loop from the center position and
the unequal values of the positive coercive field and the negative coercive
field are found, which are induced by the asymmetricity of interface dipoles. A
complete J-V curve of the junction is shown for different barrier thickness,
and the effect of the magnitude of interfacial polarization on the tunneling
current is also investigated.
