The out-of-plane electric polarization at the surface of SrTiO₃ (STO), an archetypal perovskite oxide, may stabilize new electronic states and/or host novel device functionality. This is particularly significant in proximity to atomically thin membranes, such as graphene, although a quantitative understanding of the polarization across graphene–STO interface remains experimentally elusive. Here, we report direct observation and measurement of a large intrinsic out-of-plane polarization at the interface of single-layer graphene and TiO₂-terminated STO (100) crystal. Using a unique temperature dependence of anti-hysteretic gate-transfer characteristics in dual-gated graphene-on-STO field-effect transistors, we estimate the polarization to be as large as ≈12 μC cm⁻², which is also supported by the density functional theory calculations and low-frequency noise measurements. The anti-hysteretic transfer characteristics is quantitatively shown to arise from an interplay of band bending at the STO surface and electrostatic potential due to interface polarization, which may be a generic feature in hybrid electronic devices from two-dimensional materials and perovskite oxides.

原型钙钛矿氧化物SrTiO ₃（STO）表面的平面外极化可稳定新的电子状态和/或具有新颖的设备功能。尽管对石墨烯-STO界面上的极化的定量了解在实验上还不清楚，但在靠近原子薄膜（例如石墨烯）方面，这一点尤为重要。在这里，我们报告直接观察和测量在单层石墨烯和TiO ₂终止的STO（100）晶体的界面处的大固有面外极化。使用双门石墨烯在STO上的场效应晶体管中的反滞后栅极传输特性的独特温度依赖性，我们估计极化约为≈12μCcm ^-2。，这也得到密度泛函理论计算和低频噪声测量的支持。抗滞后传递特性在定量上显示是由于STO表面的能带弯曲和界面极化引起的静电势之间的相互作用而产生的，这在二维电子材料和钙钛矿氧化物混合电子设备中可能是一个普遍特征。