张田田 副研究员 中国科学院理论物理研究所

Emergent Topology, Chirality and Quantum Geometry in Phonon spectra

时间: 2026年04月20日（星期一）下午14:30 地点: 虎溪校区理科楼物理学院 LE423 邀请人: 马大帅

报告摘要

The wavefunction of phonons encodes rich quantum information, including topological and chiral properties. In phonon systems, “chirality” carries distinct meanings: topological chirality defined in k-space and rotational chirality associated with nonzero angular momentum. In this talk, I will first introduce both types of chirality and highlight key experimental observations, such as in FeSi (the first material identified with topological phonons), circularly polarized phonons in nonsymmorphic crystals like α-HgS and Te, and spin–phonon–induced circularly polarized phonons in Co₃Sn₂S₂. I will then present our recent work: a general ab initio framework, which captures electronic order-driven symmetry breaking in lattice dynamics and applies to both insulating and metallic magnets. Applying this framework to Co₃Sn₂S₂ reveals distinct microscopic origins for the E_g and E_u phonon modes. Finally, I will discuss how to directly probe the quantum geometric tensor for phonons, including its imaginary part Berry curvature and real part quantum metric components, a approach extendable to other bosonic collective excitations.

报告人介绍

张田田，2014年本科毕业于北京师范大学；2019年获得中国科学院物理研究所理学博士学位；2019年至2022年在日本东京工业大学先后从事博士后研究、特任助理教授工作；2023年回到中国科学院理论物理研究所工作，现任副研究员。主要从事计算凝聚态物理方向的研究工作，相关成果入选两院院士评选的"2019年度中国十大科技进展新闻"之一。迄今共发表SCI论文50余篇，被引用四千余次，个人H因子24。2023年获得达摩院"青橙奖最具潜力奖"，2024年获得亚太物理学会凝聚态青年奖，2025年被选为亚太地区"麻省理工科技评论35岁以下35人"。