报告题目 (Title)：Emergent phenomena with chiral phonons（手性声子的涌现现象）

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.