报告题目：有机-无机杂化钙钛矿中铁电序形成机理的理论研究
报告人：赵锦柱 教授
时间：2024年8月29日10:00
地点：田家炳楼平星报告厅（203）
邀请人：董帅 教授
报告人简介：
赵锦柱副教授毕业于南京大学物理系，分别获得学士（2007年）和硕士学位（2010年）。他于2013年获得列日大学（比利时）凝聚态物理学博士学位。2013年至2019年，在南方科技大学担任博士后和研究助理教授。2019年11月，他加入华南师范大学物理学院，担任副教授。课题组主要研究兴趣是利用第一性原理研究固体材料中铁电、多铁序的行为以及相关奇异现象，特别是二维材料和有机-无机钙钛矿材料中的相关物理机制。相关工作得到了中国国家自然科学基金和广东省基础与应用基础研究基金的支持。
报告摘要：
The origin of Organometal halide perovskites appealing properties is sometimes assigned to their potential ferroelectric character. However, their ferroelectric nature remains under intensive debates. In our recent work, we rationalize, using first- principles calculations, how the subtle interplay between the propensity of organic molecules to bond with the inorganic framework and the appearance of iodine octahedra rotations inherent to the perovskite structure, progressively forces the orientations of methylammonium molecule, which is the key to shed light on its ferroelectric properties. We will clarify the potential ferroelectric and paraelectric behavior in tetragonal phase and the origin of anti-ferroelectric behavior in the orthorhombic phase. Along previous work, the complex arrangement of molecules and the role of tolerance factor are discussed here which will be able to explain the controversial experimental reports regarding its ferroelectric character [1]. Besides, we will clarify the origin of building FE order in Organometal halide perovskites via non-polar molecules [2]. Our work as a very timely and significant contribution in unifying and deepening our fundamental understanding of this promising material and in clarifying the long-standing debate regarding its puzzling ferroelectric behavior. The final view is rather simple and of wide interest.
图1. NH4PbI3四方相结构的铁电极化序以及竞争构型（铁电、反铁电构型）的相对能量
[1] Wen-Yi. Tong, Jin-Zhu Zhao*, Philippe Ghosez*. npj Computational Materials, 8, 165 (2022)
[2] Jia-Bin Li, Zhi-Kang Jiang, Rui Wang, Jin-Zhu Zhao* and Ruiqiang Wang*, npj Computational Materials 9, 62 (2023)