报告题目 (Title)：Emergent phenomena with chiral phonons

报告人 (Speaker)：张力发 教授（南京师范大学）

报告时间 (Time)：2024年6月20日（周四）8:30-13:00

报告地点 (Place)：校本部 D413

邀请人 (Inviter)：任伟 教授

主办部门：理学院物理系

报告摘要：

Phonons were traditionally considered as linearly polarized. Recently we predicted that phonons can be chiral and have angular momentum both in magnetic and nonmagnetic systems. The nondegenerate chiral phonons are also predicted and easily tuned in graphene/hexagonal Boron Nitride heterostructures. The chiral phonons were observed in monolayer tungsten diselenide, where the phonon chirality is confirmed by the infrared circular dichroism arising from pseudoangular momentum conservation. Our further experiments showed that through the emission of a chiral phonon the momentum-dark intervalley exciton is brightened and chiral phonons can have entanglement with photons. Recently, we predicted that the chiral phonons can propagate along high-symmetry axis of 3D materials, and can show a diode effect in chiral systems, and can induce high-temperature superconductivity. We also observed a chiral-phonon-activated spin-Seebeck effect in chiral materials very recently.

报告人简介：

Prof. L. Zhang got Ph.D degree in Physics in National University of Singapore in Jan 2012, and now is the Dean of School of Physics and Technology, Nanjing Normal University. He has been awarded Jiangsu Distinguished Professor and the leading talent of "Mass Entrepreneurship and Innovation Team" of Jiangsu Province. His research mainly focuses on phonons and quantum hermal transport, includes chiral phonon theory and application, topological phonon/magnon, interface thermal transport, etc. He has published more than 80 papers in leading international journals, including Science, Nat. Phys., Nat. Mater., Phys. Rev. Lett., Nano Lett., etc. He initiates the annual workshop on thermal transport (WTT2016) in China, and serves as the chairman of the Joint International Conference of Phonons 2018 and PTES2018.