The influence of the interfacial structure on the polarization behavior in ferroelectric tunnel junction: A first-principles study

The switching characteristics of ferroelectric tunnel junctions make them candidates for new types of logic devices. However, the effects of different electrodes and electrode/ferroelectric interfaces on the polarization behaviors of ferroelectric tunnel junctions remain unclear. In this work, first-principles calculations were utilized to study the (LaxSr1−x)MnO3/PbTiO3/SrRuO3 ferroelectric tunnel junction. It is found that the polarization of PbTiO3 is primarily determined by the interface between (LaxSr1−x)MnO3 and PbTiO3, depending on the atomic layer stacking sequence at the interface and the interfacial concentrations of La and Sr atoms. The interfacial bound charge at the (LaxSr1−x)MnO3/PbTiO3 interface is found to play an important role in the polarization variation in the PbTiO3 layer. This work indicates that by engineering the interfacial atomic concentration, ferroelectric tunnel junctions with different properties could be constructed, even if the materials of the electrodes, the ferroelectric films, and the interfacial atomic layer stacking remain unchanged, which provides novel insight for the design of ferroelectric tunnel junctions.