报告人：邹小龙 清华大学深圳国际研究生院

报告题目：Emergent optical properties of 2D materials

报告时间：2022年4月30日 下午 14：00

腾讯会议:183 969 378

报告人简介

Dr. Xiaolong Zou received his Ph.D. in physics from Tsinghua University, China, in 2011. After working as a research associate at Rice University, Houston, TX, USA, he joined Tsinghua-Berkeley Shenzhen Institute (TBSI), part of Tsinghua Shenzhen International Graduate School, Tsinghua University, as an Assistant Professor in 2016 and promoted to Accociate Professor in 2019. Dr. Zou's current research focuses on the theoretical description of magnetic and optical properties of 2D materials and their coupling, as well as the growth mechanism of 2D materials. He has published over 90 papers in peer-refereed journals, including 1 Nature, 2 Nature Materials, 6 Nature Communications, 3 Materials Today, 1 Accounts of Chemical Research, 5 Advanced Materials, 8 Nano Letters, 11 ACS Nano. These papers receive total citations over 10000 and an H-index of 40. He has been invited to write book/chapter by several prestigious publishers, including Science Press, and Cambridge University Press.

报告摘要

Two-dimensional (2D) materials are ideal platforms for exploring emerging optical behaviors, at unprecedentedly high temperature and feasible control. Here, we report our systematic study on the effects of different band topologies and moiré superlattices on the optical properties of 2D systems. Different 2D materials with characteristic band topologies can be adopted to achieve various long-sought high-temperature excitonic quantum behaviors, including electron-hole liquid in a new-phase (γ-phase) group IV monochalcogenides (This new phase has been synthesized recently.), excitonic Bose-Einstein Condensation in TiS3, and saddle excitons in β-phase group IV monochalcogenides. By introducing twist in trilayer black phosphorous (TTbP) with strong interlayer coupling and deep 1D moiré potential, we observed remarkably strong moiré optical resonances even at a large twist angle of 19°. Combining twisting, pressure, and electric field, controllable tuning of bandgap, bandwidth, and dimension of moiré bands can be achieved, thus establishing TTbP as an attractive platform to explore strongly correlated moiré electronic and excited states in different dimensions, as well as tunable opto-electronic applications.