报告人：李西阳 副研究员（中国科学院物理研究所）

邀请人：李志远 教授

地点：物理楼（18号楼）二楼213会议室

题目： Frustrated Spin-1/2 Chains in a Correlated Metal Ti4MnBi2

时间：2025年11月5日（星期三）上午10:00-11:00

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                                                 物理与光电学院

                                     2025年10月31日

内容摘要：

Electronic correlations lead to heavy quasiparticles in 3D metals, and their collapse can destabilize magnetic moments. It is an open question whether there is an analogous instability in 1D systems, unanswered due to the lack of metallic spin chain materials. We report neutron scattering measurements and DMRG calculations establishing spinons in the correlated metal Ti4MnBi2, confirming that its magnetism is 1D [1]. Ti4MnBi2 is inherently frustrated, forming near a QCP separating different T = 0 phases of the J1-J2 XXZ model. 1D magnetism dominates and is barely affected by weak interchain coupling down to 15 mK [2]. It is the first metallic spin chain where 3D conduction electrons strongly correlate via coupling to 1D magnetic moments, offering a new platform to study the transverse field Ising model with magnetic frustration.

References

[1] Xiyang Li*, A. Nocera, K. Foyevtsova, et al., Nature Materials 24, 716–721 (2025).

[2] Xiyang Li*, K. M. Kojima, M. C. Aronson, et al., “Proximal Quantum Spin Liquid in Spin-1/2 chain Metal Ti4MnBi2”, (In preparation).

报告人简介： Xiyang is an Associate Professor at the Institute of Physics, Chinese Academy of Sciences (IOP, CAS), where he employs neutron scattering and μSR to study spin dynamics in quantum magnets. He received PhD in 2019 from IOP, CAS, under Prof. Fangwei Wang, uncovering the mechanism of ultralow thermal conductivity in α-MgAgSb thermoelectrics. In collaboration with Prof. Xun-Li Wang (CityU, Hong Kong), he achieved the first observation of high-frequency transverse phonons in metallic glasses. As a postdoc at UBC with Prof. Meigan Aronson, he grew single crystals and explored novel quantum phenomena in the 1D spin chain compound Ti₄MnBi₂. He has published ~20 papers in Nat. Mater., Phys. Rev. Lett., and Nat. Commun., and reviews for leading journals including PRL, Nat. Commun., and PRB.