报告人：Juan XIA（University of Electronic Science and Technology of China）

时 间：2022年11月16日（周三）下午14:00-15:30

地 点：线上会议， 腾讯会议：773-213-643

摘要：

Two-dimensional (2D) transition metal dichalcogenides (TMDs) and their van der Waals heterostructures (vdWs HSs), exhibit attractive optical and optoelectronic properties thanks to the different band alignments and interlayer interactions. Further, their sensitivity to interlayer distance allows effective tuning of material properties through external modulation of lattice parameters. Therefore, it is of both fundamental and practical importance to explore interlayer excitons in vdWs HSs, especially their dynamic response and underlying mechanisms to different tuning techniques. So far, only limited changes in lattice parameters have been achieved (e.g., less than 2% volume change using strain engineering, or ~5% interlayer spacing using piston-cylinder setup), hampering effective tuning of physical properties in vdWs HSs.

In this talk, we demonstrate effective tuning of the excitonic states by controlling the interlayer distance in TMDs vdWs HSs, and further tune the interlayer spacing and thus the band structure using hydrostatic pressure. In addition, we perform density functional theory (DFT) calculations and achieve good agreement with the experimental observations, revealing a pressured-induced changeover in the band structure of the HSs. This may offer new insights into the strong interlayer interaction and electron-phonon coupling in TMDs via pressure engineering, which can be exploited for designing new excitonic devices based on 2D vdWs HSs.

简历：

Dr. Juan XIA is a professor in the Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China. She received her BSc from Sichuan University in China and her PhD degree from Nanyang Technological University in Singapore. Her main research areas involve two-dimensional materials and related physical properties. Specifically, she has been active in the study of interlayer coupling effect in 2D materials and heterostructures under extreme conditions.

联系方式：sunlinfeng@bit.edu.cn

邀请人： 孙林锋 教授

网 址：http://physics.bit.edu.cn/

承办单位：7003全讯入口、先进光电量子结构设计与测量教育部重点实验室