Yun Hwanhui, Topsakal Mehmet, Prakash Abhinav, Jalan Bharat, Jeong Jong Seok, Birol Turan, Mkhoyan K Andre
Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA.
Nuclear Science and Technology Department, Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973, USA.
Sci Adv. 2021 Jan 15;7(3). doi: 10.1126/sciadv.abd4449. Print 2021 Jan.
A line defect with metallic characteristics has been found in optically transparent BaSnO perovskite thin films. The distinct atomic structure of the defect core, composed of Sn and O atoms, was visualized by atomic-resolution scanning transmission electron microscopy (STEM). When doped with La, dopants that replace Ba atoms preferentially segregate to specific crystallographic sites adjacent to the line defect. The electronic structure of the line defect probed in STEM with electron energy-loss spectroscopy was supported by ab initio theory, which indicates the presence of Fermi level-crossing electronic bands that originate from defect core atoms. These metallic line defects also act as electron sinks attracting additional negative charges in these wide-bandgap BaSnO films.
在光学透明的BaSnO钙钛矿薄膜中发现了具有金属特性的线状缺陷。由Sn和O原子组成的缺陷核心独特的原子结构，通过原子分辨率扫描透射电子显微镜（STEM）得以可视化。当用La掺杂时，取代Ba原子的掺杂剂优先偏析到与线状缺陷相邻的特定晶体学位置。用电子能量损失谱在STEM中探测到的线状缺陷的电子结构得到了从头算理论的支持，这表明存在源自缺陷核心原子的费米能级交叉电子能带。这些金属线状缺陷还充当电子陷阱，在这些宽带隙BaSnO薄膜中吸引额外的负电荷。
