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 by Berry curvature 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 [1] (the first material identified with topological phonons), α-HgS and Te [2], and molecular Berry curvature [3]–induced time-reversal symmetry breaking and phonon splitting in Co₃Sn₂S₂ [4].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 E₉ and Eᵤ phonon modes [5]. 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, an approach extendable to other bosonic collective excitations [6].

References:

[1] T. Zhang, et al., Phys. Rev. Lett., 120, 016401 (2018)

[2] Ishito, et al., Nat. Phys., 19, 35-39 (2023); T. Zhang, et al., Nano Lett., 23, 7561–7567 (2023)

[3] Mead and Truhlar, J. Chem. Phys.70, 2284–2296 (1979); M.V. Berry. Proc. R. Soc. Lond. A, 392, 45-57 (1984); Saparov, et al., Phys. Rev. B, 105, 064303 (2022)

[4] Yang, et al, Phys. Rev. Lett., 134, 196905 (2025); Che, et al., Phys. Rev. Lett., 134, 196906 (2025)

[5] Zhang, Wang, Zhang and T. Zhang^*, Sci. Adv., 12, eaed7081 (2026)

[6] Wu, Oka, Murakami and T. Zhang*. arXiv: 2601.13963 (2026)

报告人简介：

　　张田田，中国科学院理论物理研究所研究员。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，并入选国家级海外高层次人才。主要从事计算凝聚态物理方向的研究工作，发展拓扑物态理论，挖掘新型拓扑量子材料及电子、声子、电声耦合等相关物性。曾先后成功计算预言了拓扑外尔声子材料FeSi、BaPtGe，拓扑节点线声子材料MoB2，建立国际上首个拓扑电子材料数据库Materiae，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，被引用五千余次。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”。