Theories for electrical detection and control of altermagnetism and nonlinear magnetization

by Prof. Haizhou Lu (卢海舟) (Southern University of Science and Technology)

Wednesday 6 May 2026, 15:00 → 16:00 Asia/Shanghai

Tsung-Dao Lee Institute/N6F-N600 - Lecture Room (Tsung-Dao Lee Institute)

Host: Prof. Anyuan Gao  

Venue: TDLI Meeting Room N600

Tencent Meeting link: https://meeting.tencent.com/dm/4RLRVctzpIaN

Meeting ID: 259296394, no password

 

Abstract:

Using only electricity to detect, generate, and control magnetism is of great potentials in applications but remains challenging. In this talk, I will introduce our theories on using only pure electric approaches to detect, switch, and generate unconventional magnetism, including altermagnetism and nonlinear magnetization.

Altermagnetism is an unconventional collinear antiferromagnetism. Its spin-opposite sublattices cannot be related by inversion or translation. This property gives altermagnetism the advantages of both ferromagnetism and antiferromagnetism thus are promising in applications. I will introduce how to use Coulomb drag and nonlinear Hall effect to detect altermagnetism and how to use only electric current to switch the Neel order of altermagnetism deterministically.

The Christoffel symbol is an essential quantity in Einstein’s general theory of relativity. We discover that an electric field can induce a nonlinear magnetization in quantum materials, described by the quantum Christoffel symbol. We identify many 2D material candidates that host this quantum Christoffel nonlinear magnetization. This nonlinear Christoffel magnetization can be probed by optical techniques such as magneto-optical Kerr spectroscopy. More importantly, this quantum Christoffel nonlinear magnetization gives a paradigm of how geometry dictates physics.

 

References: 

[1] Yiyuan Chen, Xiaoxiong Liu, Hai-Zhou Lu, and X. C. Xie, "Electrical switching of altermagnetism", Phys. Rev. Lett. 135, 016701 (2025). 

[2] Haojie Lin, Songbo Zhang, Hai-Zhou Lu, and X. C. Xie, "Coulomb drag in altermagnets", Phys. Rev. Lett. 134, 136301 (2025). 

[3] R. Y. Chu, L. Han, Z. H. Gong, H. Z. Lu, C. Song, et al., "Third-order nonlinear Hall effect in altermagnet RuO2", Phys. Rev. Lett. 135, 216703 (2025). 

[4] Zhen-Hao Gong, Zhi-Hao Wei, Hai-Zhou Lu, and X. C. Xie, "Identifying geometric third-order nonlinear transport in disordered materials", arXiv:2510.24239. 

[5] Xiao-Bin Qiang, Xiaoxiong Liu, Hai-Zhou Lu, X. C. Xie, "Quantum Christoffel nonlinear magnetization", Phys. Rev. Lett. 136, 056302 (2026).

[6] Xuan Qian, Xiao-Bin Qiang, W. Z., Hai-Zhou Lu, Yang Ji, Kaiyou Wang, et al., "Probing quantum geometric nonlinear magnetization via second-harmonic magneto-optical Kerr effect", Phys. Rev. B 113, L041407 (2026).

 

Biography:

Haizhou Lu obtained his Ph.D. in Physics from Institute for Advanced Study at Tsinghua University in 2007. From 2007 to 2015, he was a Postdoc then Research Assistant Professor at the University of Hong Kong. He joined SUSTech in 2015 and now is a Chair Professor and Head of Department of Physics. His research is focused on the quantum transport theories in topological matter. His publications can be found at https://scholar.google.com/citations?user=9-SL76YAAAAJ&hl=en