报告人：高鹏研究员（北京大学物理学院）

时间：9月12日（周一）下午15点-16点

地点：物理学院新楼5楼多功能报告厅

摘要：Ferroelectrics have numerous applications including high-density and non-volatile memories, acoustic devices, and sensors. These devicesare operated bypolarization switching under external excitations,e.g.electrical and mechanical fields. The switching initiated with nucleation and followed by growth of favorably oriented domains is a heterogeneous process, which is dominated by defects. Understanding the dynamics and kinetics of this process is vital for the device design and optimization.By using thein situbiasing and indentation TEM techniques, a few interesting phenomena have been observed: (a) The nucleation of ferroelectric domains always occurs at the interfaces between ferroelectrics and electrodes. (b) During switching, the high-energy domain wall relaxes, leading to retention loss in ferroelectric memories. (c) The mobility/immobility of ferroelastic domain walls depends on the specific microstructures. Some of ferroelastic domains can be switched by either electrical or mechanical fields. (d) The immobile ferroelastic domains strongly interact with ferroelectric domain wall, resulting in unexpected ‘glassy’ polarization at the charged domain wall. (e) The dislocations act as weak pining centers for 180° domain wall motion, but they can strongly stabilize the ferroelastic domains.

简介：

高鹏，北京大学物理学院研究员，博士生导师。长期从事透射电子显微学相关的研究。近期的主要研究兴趣是基于高能量分辨的电子能量损失谱技术、高空间分辨的图像定量化技术、高时间分辨的原位探测技术来研究陶瓷、薄膜、低维纳米材料的结构与物性关系。共发表论文40余篇，引用1000多次，包括9篇Nature Commun./Mater./Nano.和1篇Science。曾入选日本振兴学会（JSPS）外国人特别研究员。

邀请人：廖蕾教授