报告题目：Atomic and electronic structures of 2D electronic materials and their heterostructures

报告人：Prof. Chih-Kang Shih

（Department of Physics, The University of Texas at Austin）

报告时间：2017年6月7日（周三）上午10:00

报告地点：物理学院新楼大报告厅

报告摘要：

The emerging atomic layer materials offer a remarkably wide range of building blocks of nanostructures ranging from metals (e.g. graphene), large gap insulators (BN), to semiconductors (transition metal dichalcogenides and black phosphorous). 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, tunability in material properties by doping and strain, and the relative ease of integration with other electronic and photonic devices. This talk will be focused on the our recent work in probing the atomic and electronic structure of transition metal dichalcogenides (TMDs) and their heterostructures, including both vertical and lateral structure

I will first introduce a comprehensive form of scanning tunneling spectroscopy (STS) which allows us to probe not only the quasi-particle band gaps but also the critical point energy locations and their origins in the Brillouin Zone (BZ) can be revealed using this comprehensive form of STS. By using this new method, we unravel the systematic trend of the critical point energies for TMDs due to atomic orbital couplings, spin-orbital coupling and the interlayer coupling. By using the vertically stacked MoS2/WSe2, I will show how interlayer coupling can be used as a new designing parameter to create a lateral 2D electronic superlattices. I will then turn attention to MoS2/WSe2 lateral heterostructure where I will show a novel method to probe 2D strain tensor and how the strain changes the band profile as well as the band alignment at the interface.

报告人简介：

Chih-Kang (Ken) Shih received his PhD in Applied Physics from Stanford University in 1988. He joined the faculty of the University of Texas at Austin in 1990 as an assistant professor in the Department of Physics, and was later appointed Assistant Professor of Physics. In 2001, he was promoted to the full Professor rank. Since 2004 he has held the Jane and Roland Blumberg Professorship in Physics. Shih is a Fellow of the APS, and he received the 2011 Distinguished Alumni Award from the National Tsing-Hwa University. He has specialized in mesoscopic physics, solid state physics, scanning tunnelling microscopy and spectroscopy, nanoscale optical imaging and spectroscopy, and thin film growth.

邀请人：张晨栋教授