Speaker
Description
Antiferromagnetic conductors with suitably broken spatial symmetries host spin-polarized bands even in the absence of spin-orbit coupling, leading to transport phenomena commonly observed in metallic ferromagnets. Here we show that, in the two-dimensional (2D) limit, an electric field can control the relevant symmetries. Two situations are discussed. First, we show by first-principles simulations and magnetotransport experiments that a perpendicular electric displacement field can switch the spin polarization of the conduction band on and off in an antiferromagnetic van der Waals bilayer, such as CrPS$_4$. Second, we consider the case of altermagnets, where spin-valley locking can give rise to band extrema (valleys) at different locations in the Brillouin zone for opposite spins. By screening high-throughput databases of 2D magnetic materials, we find a potential candidate with suitable symmetries, where an electric field can lift the degeneracy between valleys with opposite spin and thus create a simultaneous spin and valley polarization. First-principles simulations predict a sizeable effect that meets the requirements for applications in spin-valleytronics.
Acknowledgements
We acknowledge financial support from Ministero Italiano dell'Università e della Ricerca through the PRIN2022 project SECSY (CUP E53D23001700006), funded by the European Union – NextGenerationEU.
