【报告题目】 Atomic and electronic structures of transition metal dichalcogenides heterostructures
【报 告 人】 张晨栋 教授
武汉大学物理科学与技术学院
【时 间】 2019-05-29 4:00 pm (Wedensday)
【地 点】 理工楼801报告厅
【报告摘要】
The emerging atomic layer materials offer a remarkably wide range of building blocks of nanostructures. Key advantages of these van der Waals materials include a broad span of energy gaps, flexibility of stacking different types of materials to form heterostructures, and the tunability in material properties by doping and strain. This talk will be focused on our recent work in probing the atomic and electronic structure of transition metal dichalcogenides (TMDs) heterostructures, including both vertical and lateral structure. I will first show that in vertically stacked MoS2/WSe2heterostructures, how the interlayer coupling can be used as a new designing
parameter to create a lateral 2D electronic superlattices. For lateral WSe2-MoS2 heterostructure, we present a novel method to determine the anisotropic strain based on Moiré pattern imaging. The 2×2 strain tensor is imaged with nanometer spatial resolution. We also determine the band offset across the junction and show that the strain effect converts the otherwise type-II into type-I band alignment. Moreover, a “line interface specific” electronic structure due to the specific bonding configuration is discovered at the interface.
References:
[1] C. D. Zhang et. al. “Interlayer Couplings, Moiré Patterns, and 2D Electronic Super-lattices in MoS2/WSe2 Hetero-bilayers”, Science Advances 3, e1601459 (2017).
[2] C. D Zhang* et.al. “Strain distributions and Their Influences on electronic structures of WSe2-MoS2 laterally strained heterojunctions”, Nature Nanotechnoly 13, 152–158 (2018).
[3] C. D. Zhang*et. al. “Engineering Point-Defect States in Monolayer WSe2”, ACS Nano 13, 1595–1602 (2019)
【报告人简介】
Dr. Chendong Zhang obtained his Ph.D in condensed matter physics from the Institute of Physics, Chinese Academy of Sciences in 2011. From 2011 to 2016, he worked in the University of Texas at Austin as a postdoctoral scholar. He joined the Wuhan University in 2017 as a professor in the School of Physics and Technology. He has specialized in low dimensional quantum materials, scanning tunneling microscopy/spectroscopy and the thin film growth.