Recently, a research team led by Professor Haijun Zhang from the School of Physics at Nanjing University, in collaboration with Professor Huaiqiang Wang from Nanjing Normal University, has made new progress in the study of altermagnetic multiferroics. The team proposed the concept of altermagnetic type-II multiferroicity and, by combining symmetry analysis with a metal-ligand hybridization model, revealed how altermagnetic Néel order induces spontaneous electric polarization and lock it to the orientation of the Néel vector. Through a symmetry analysis, the researchers classified the possible locking relations in two-dimensional altermagnets into eight categories and identified monolayer MgFe₂N₂ as an example material, where the out-of-plane polarization follows P_z ∝ cos(2ϕ) with pronounced momentum-dependent spin splitting. This mechanism links the unconventional spin structure of altermagnets to the magnetically-induced ferroelectricity of type-II multiferroics, providing a pathway for the search of new magnetoelectric coupling materials. This work was published in Nature Communications, entitled “Altermagnetic type-II Multiferroics with Néel-order-locked Electric Polarization”.

Figure 1. Schematic illustration of the mechanism of multiferroicity induced by altermagnetic order.

Publication link: https://doi.org/10.1038/s41467-026-73750-5