SEMINARIO GENERALE

Speaker:  Jeroen van den Brink (Institute for Theoretical Solid State Physics, Dresde)

Data:   Wednesday Apr 16, 2025, 4:00 PM -6:00 PM
Luogo: Aula Conversi (Ed. Marconi)
 

It has recently been understood that altermagnetic materials constitute a novel, third fundamental class of magnetically ordered materials, alongside with ferro- and antiferromagnets [1]. They share with conventional antiferromagnets the feature of a vanishing net magnetization. At the same time they show a spin-splitting of electronic bands, just as in ferromagnets, but which is absent in conventional antiferromagnets. Around 60 existing altermagnetic materials have been identified on the basis of their electronic structure [2]. We will discuss several physical properties that render altermagnets different from canonical antiferro-, ferro- and ferri-magnets and how these might be useful for spintronics. These include spin and heat transport properties as well as piezomagnetic responses. By symmetry in principle also a Hall effect is allowed in altermagnets that occurs in absence of any external magnetic field or net magnetization, which we illustrate in terms for a simple model altermagnet [3].

References:
[1] L. Smejkal, R. Gonzalez-Hernandez, T. Jungwirth, and J. Sinova, Crystal time-reversal symmetry breaking and spontaneous hall effect in collinear antiferromagnets, Science Advances 6, eaaz8809 (2020).
[2] Y. Guo, H. Liu, O. Janson, I.C. Fulga, J. van den Brink, and J.I. Facio, Spin-split collinear antiferromagnets: A large-scale ab-initio study, Materials Today Physics, 32, 100991 (2023).
[3] T. Sato, S. Haddad, I.C. Fulga, F.F. Assaad, and J. van den Brink, Altermagnetic anomalous Hall effect emerging from electronic correlations, Phys. Rev. Lett. 133, 086503 (2024).