Broken Kramers Degeneracy in Altermagnetic MnTe

Altermagnetism is a newly identified fundamental class of magnetism with vanishing net magnetization and time-reversal symmetry broken electronic structure. Probing the unusual electronic structure with nonrelativistic spin splitting would be a direct experimental verification of an altermagnetic phase. By combining high-quality film growth and in situ angle-resolved photoemission spectroscopy, we report the electronic structure of an altermagnetic candidate, α−MnTe. Temperature-dependent study reveals the lifting of Kramers degeneracy accompanied by a magnetic phase transition at TN=267 K with spin splitting of up to 370 meV, providing direct spectroscopic evidence for altermagnetism in MnTe.Received 21 August 2023Accepted 14 November 2023DOI:https://doi.org/10.1103/PhysRevLett.132.036702© 2024 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasElectronic structureMagnetic phase transitionsMagnetismTechniquesAngle-resolved photoemission spectroscopyDFT+DMFTDensity functional theoryMolecular beam epitaxyCondensed Matter, Materials & Applied Physics