Altermagnetism: A New Class of Magnetic Order
Speaker: Govinda Kharal
Affiliation: University of South Carolina
Date: February 13th
Abstract: Magnetism in solids is usually understood in terms of ferromagnets and antiferromagnets, based on whether a material has a net magnetization. Recently, however, a new type of magnetic order – altermagnetism – has been identified, offering a fresh perspective beyond this traditional classification. Altermagnets have zero net magnetization, much like antiferromagnets, yet their electronic bands show strong spin splitting similar to what is typically seen in ferromagnets. Importantly, this behavior does not rely on spin-orbit coupling or complex noncollinear spin structures but instead originates from the underlying crystal and magnetic symmetries that break spin degeneracy in momentum space [1].
In this seminar, I will introduce the basic idea of altermagnetism from a symmetry and band-structure point of view and explain how it differs from both conventional ferromagnets and antiferromagnets. Using a few representative examples, including MnTe and CrSb, I will show how altermagnetic order appears in electronic structure and transport measurements. I will also discuss experimental signatures such as spin polarized bands and anomalous Hall effects that arise despite the absence of net magnetization and briefly highlight the potential applications of altermagnets [2].
References:
[1] Libor Šmejkal, Jairo Sinova, and Tomas Jungwirth, Phys. Rev. X 12, 031042 (2022)
[2] C. Song et al, Nat. Rev. Mater. 10, 473–485 (2025