Origin of temperature-dependent magnetism in spin-orbit-coupled transition metal compounds and insulating state in the honeycomb iridate Cu2IrO3

by Prof. Ying Li(李颖） (Xi'an Jiaotong University)

Friday 23 Jan 2026, 10:30 → 11:30 Asia/Shanghai

Tsung-Dao Lee Institute/N4F-N400 - meeting room (Tsung-Dao Lee Institute)

Host: Prof. Ruidan Zhong  

Venue: TDLI Meeting Room N400

Tencent Meeting link:    https://meeting.tencent.com/dm/zj0w0mTpv6Bz  Meeting ID: 317375921, no password

 

Abstract:

One of the most common practices in quantum materials is to fit experimentally measured magnetic susceptibilities to a Curie-Weiss law which provides information on their magnetism. Such a law is not valid in systems where spin-orbit coupling is significant. Kotani proposed decades ago a model which has been widely used but inexplicably fails in many 4d- and 5d-transition-metal-based compounds. We uncover the origin of the failures and propose a generalized model to describe their magnetism[1]. We also present possible microscopic origin of the unexpected insulating behavior reported in the honeycomb Kitaev candidate Cu2IrO3 through a combination of crystal symmetry analysis and density functional theory calculation. Our study suggests that this material hosts an instability towards charge ordering of the Ir ions, with alternating magnetic Ir4+ and nonmagnetic Ir3+ ions arranged on the honeycomb lattice. The effective lattice for magnetic interactions is formed by two interpenetrated triangular sublattices of different magnetic ions (Ir4+ and Cu2+)[2].

 

References:

[1] Y. Li , R. Seshadri , S. D. Wilson , et al., Phys. Rev. Res. 7, L012083 (2025)

[2] Y. Li, R. D. Johnson, Y. Singh, R. Coldea, and R. Valentí, Phys. Rev. B 111, 245122 (2025)

 

Biography:

Li Ying (李颖）has been an associate professor at the School of Physics, Xi'an Jiaotong University since 2019. She completed both her undergraduate and master’s degrees at Xi'an Jiaotong University and earned her Ph.D. from Goethe University Frankfurt in Germany in 2017. She subsequently conducted postdoctoral research from 2017 to 2019. In 2023, she was awarded a Humboldt Research Fellowship to work as a visiting scholar at the Technical University of Munich. Her research centers on theoretical condensed matter physics, with a specific focus on fundamental theories of strongly correlated systems, with particular emphasis on candidate materials for quantum magnetism.