Ferroelectricity-like Polarization and Metallicity at GdAlO₃/SrTiO₃ Heterointerfaces

Application of multifunctional integrated devices represents a main trend in the future. However, it is still a great challenge to realize ferroelectric metals in a single system. Here, we report the coexistence of metallicity and ferroelectricity-like polarization at GdAlO₃/SrTiO₃ heterointerfaces. The results show that the asymmetric bistable polarization in the GdAlO₃ film is attributed to the spontaneous polarization of oxygen vacancies. Furthermore, the transport property of GdAlO₃/SrTiO₃ heterointerfaces can be significantly manipulated by switching the polarization state. It is observed that the switchable conductance significantly improves under the influence of a polarization state at 6 V. Its change in the resistance is about 17.2% under 10 V, which accelerates the commercial application of oxide devices.