Electric Polarization Switching on an Atomically Thin Metallic Oxide
Mao Ye, Songbai Hu, Yuanmin Zhu, Yubo Zhang, Shanming Ke, Lin Xie, Yuan Zhang, Sixia Hu, Dongwen Zhang, Zhenlin Luo, Meng Gu, Jiaqing He, Peihong Zhang, Wenqing Zhang, Lang Chen
Abstract
Materials with reduced dimensions have been shown to host a wide variety of exotic properties and novel quantum states that often defy textbook wisdom. Polarization switching and metallic screening are well-known examples of mutually exclusive properties that cannot coexist in bulk solids. Here we report the fabrication of (SrRuO3)1/(BaTiO3)10 superlattices that exhibits reversible polarization switching in an atomically thin metallic layer. A multipronged investigation combining structural analyses, electrical measurements, and first-principles electronic structure calculations unravels the coexistence of two-dimensional (2D) metallicity in the SrRuO3 layer accompanied by the breaking of inversion symmetry, supporting electric polarization along the out-of-plane direction. Such a 2D ferroelectric-like metal paves a novel way to engineer a quantum multistate with unusual coexisting properties, such as ferroelectrics and metals, manipulated by external fields.