  Based on the structure predicted in a ferroelectric tunnel junction in the
resent density functional theory study, we investigate the electron transport
through the FTJ with asymmetric interfaces, i.e., one interface dipole is
pinned and the other interface dipole is switchable. Tuneling electroresistance
can be induced due to the nonswitchable interface dipole in FTJs with symmetric
electrodes. Compared with the dependence relationship between TER and the
polarization of switchable interface, TER is not sensitive to the variation of
the polarization of pinned interface. A large TER can be achieved when the
pinned polarization points to the ferroelectric film and low interface
dielectric constants. In addition, effect of electrode on TER in the structure
is also discussed.
