Engineering of multiferroic BiFeO grain boundaries with head-to-head polarization configurations  

原子尺度制造BiFeO_(3)中头对头极化界面

作　　者：Mingqiang Li Shuzhen Yang Ruochen Shi Linglong Li Ruixue Zhu Xiaomei Li Yang Cheng Xiumei Ma Jingmin Zhang Kaihui Liu Pu Yu Peng Gao 李明强;杨树圳;时若晨;李玲龙;朱瑞雪;李晓梅;程阳;马秀梅;张敬民;刘开辉;于浦;高鹏(Electron Microscopy Laboratory,School of Physics,Peking University,Beijing 100871,China;International Center for Quantum Materials,School of Physics,Peking University,Beijing 100871,China;Academy for Advanced Interdisciplinary Studies,Peking University,Beijing 100871,China;Peking University Shenzhen Graduate School,Peking University,Shenzhen 518055,China;TCL China Star Optoelectronics Technology Co.,Ltd.,Shenzhen 518132,China;Beijing National Laboratory for Condensed Matter Physics and Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China;State Key Laboratory for Mesoscopic Physics,School of Physics,Peking University,Beijing 100871,China;Collaborative Innovation Centre of Quantum Matter,Beijing 100871,China;State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics,Tsinghua University,Beijing 100084,China)

机构地区：[1]Electron Microscopy Laboratory,School of Physics,Peking University,Beijing 100871,China [2]International Center for Quantum Materials,School of Physics,Peking University,Beijing 100871,China [3]Academy for Advanced Interdisciplinary Studies,Peking University,Beijing 100871,China [4]Peking University Shenzhen Graduate School,Peking University,Shenzhen 518055,China [5]TCL China Star Optoelectronics Technology Co.,Ltd.,Shenzhen 518132,China [6]Beijing National Laboratory for Condensed Matter Physics and Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China [7]State Key Laboratory for Mesoscopic Physics,School of Physics,Peking University,Beijing 100871,China [8]Collaborative Innovation Centre of Quantum Matter,Beijing 100871,China [9]State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics,Tsinghua University,Beijing 100084,China.

出　　处：《Science Bulletin》2021年第8期771-776,M0003,共7页科学通报（英文版）

基　　金：supported by the National Basic Research Program of China(2016YFA0300804);the National Natural Science Foundation of China(51672007 and 11974023);Key Area R&D Program of Guangdong Province(2018B010109009);the Key R&D Program of Guangdong Province(2018B030327001);National Equipment Program of China(ZDYZ2015-1);the‘‘2011 Program”Peking-Tsinghua-IOP Collaborative Innovation Centre for Quantum Matter;supported by the National Basic Research Program of China(2016YFA0301004);the National Natural Science Foundation of China(51872155,52025024);the Beijing Advanced Innovation Center for Future Chip(ICFC)。

摘　　要：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 O_(3) 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.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 O_(3)中制备几何结构和电荷密度可调控的带电界面.这些Bi Fe O_(3)晶界是以Sr Ti O_(3)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 O_(3)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 O_(3)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 O_(3)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.

关 键 词：HEAD-TO-HEAD Grain boundaries Atomic structure BiFeO_(3) 

分 类 号：TB383.2[一般工业技术—材料科学与工程] TM221[电气工程—电工理论与新技术]