【摘要】 铁电薄膜中的带电界面会产生低维的受限电荷,从而诱导很多诸如二维电子气等新奇的物理性质,在未来的纳米电子器件中具有很大的应用潜力.然而这些带电界面通常会产生巨大的退极化场,很难稳定存在.本文利用晶界工程在多铁Bi Fe O3中制备几何结构和电荷密度可调控的带电界面.这些Bi Fe O3晶界是以Sr Ti O3双晶衬底为模板制备的,具有厘米级的二维尺寸和小于1 nm的厚度.通过压电力显微镜和球差矫正透射电子显微镜测量Bi Fe O3晶界处极化取向和原子结构,我们发现10°, 22.6°和36.8°的Bi Fe O3晶界都会形成头对头的极化构型.另外,极化大小在晶界附近并没有受到明显的抑制,表明在晶界处自由载流子和缺陷等很好地屏蔽了极化电荷.因此,这种头对头的极化导致晶界处聚集极化电荷,形成了一个带电的二维界面.通过控制双晶模板的角度可以调控Bi Fe O3中晶界的角度和携带的电荷量,为设计基于带电界面的器件提供了新思路.更多还原

【Abstract】 Confined low dimensional charges with high density such as two-dimensional electron gas(2 DEG) at interfaces and charged domain walls in ferroelectrics show great potential to serve as functional elements in future nanoelectronics. However, stabilization and control of low dimensional charges is challenging,as they are usually subject to enormous depolarization fields. Here, we demonstrate a method to fabricate tunable charged interfaces with ～77°, 86° and 94° head-to-head polarization configurations in multiferroic Bi Fe O3 thin films by grain boundary engineering. The adjacent grains are cohesively bonded and the boundary is about 1 nm in width and devoid of any amorphous region. Remarkably, the polarization remains almost unchanged near the grain boundaries, indicating the polarization charges are well compensated, i.e., there should be two-dimensional charge gas confined at grain boundaries. Adjusting the tilt angle of the grain boundaries enables tuning the angle of polarization configurations from 71° to 109°,which in turn allows the control of charge density at the grain boundaries. This general and feasible method opens new doors for the application of charged interfaces in next generation nanoelectronics.更多还原