中山大学物理与天文学院

报告摘要:

In van der Waals bilayer structures of transition metal dichalcogenides, a small twist angle between the two layers leads to the appearance of a large scale moiré pattern. In a heterobilayer, these moiré effects realize superstructures of nanodot confinements for long‐lived interlayer excitons. At given atomic registry, the spin‐triplet and spin‐singlet excitons have distinct valley polarization selection rules, allowing the selective optical addressing of both the exciton valley and the spin‐singlet/triplet configurations. In a homobilayer moiré superlattice, the spatially varying layer hybridization can result in a luminescence anomaly of the moiré trapped excitons, where a tiny displacement can dramatically increase the brightness and changes polarization from circular to linear. The spatially varying layer hybridization is also at the heart of the recently discovered quantum spin Hall effect in homobilayer MoTe2.

报告人简介:

俞弘毅，本科毕业于北京大学物理系，博士毕业于中科院物理所，曾在香港大学物理系从事博士后和研究助理教授职位，现为中山大学物理与天文学院教授。近些年来主要研究二维层状半导体领域的激子光电性质、自旋/赝自旋操控和关联电子晶体中的新奇元激发等理论，其多个理论预言已被后续实验证实，产生了广泛国际影响。现已应邀撰写综述3篇、专著章节2章，并在2016年美国物理学会三月会议上应邀报告其研究成果。已发表研究论文60余篇，web of science被引10000余次，入选科睿唯安评选的2021、2022和2023年度交叉学科领域高被引科学家名单。

邀请人：许杨 特聘研究员（82648119）