Altermagnetic lifting of Kramers spin degeneracy

• 成果类型: Article
• 署名作者: Krempasky, J.; Smejkal, L.; D'Souza, S. W.; Hajlaoui, M.; Springholz, G.; Uhlirova, K.; Alarab, F.; Constantinou, P. C.; Strocov, V.; Usanov, D.; Pudelko, W. R.; Gonzalez-Hernandez, R.; Hellenes, A. Birk; Jansa, Z.; Reichlova, H.; Soban, Z.; Betancourt, R. D. Gonzalez; Wadley, P.; Sinova, J.; Kriegner, D.; Minar, J.; Dil, J. H.; Jungwirth, T.
• 署名单位: Swiss Federal Institutes of Technology Domain; Paul Scherrer Institute; Johannes Gutenberg University of Mainz; Czech Academy of Sciences; Institute of Physics of the Czech Academy of Sciences; University of West Bohemia Pilsen; Johannes Kepler University Linz; Charles University Prague; University of Zurich; Universidad del Norte Colombia; University of Nottingham; Swiss Federal Institutes of Technology Domain; Ecole Polytechnique Federale de Lausanne
• 刊物名称: Nature
• ISSN/ISSBN: 0028-5184
• DOI: 10.1038/s41586-023-06907-7
• 发表日期: 2024-02-15
• 页码: 517-+
• 关键词: scattering; beamline; adress

摘要

Lifted Kramers spin degeneracy (LKSD) has been among the central topics of condensed-matter physics since the dawn of the band theory of solids(1,2). It underpins established practical applications as well as current frontier research, ranging from magnetic-memory technology(3-7) to topological quantum matter(8-14). Traditionally, LKSD has been considered to originate from two possible internal symmetry-breaking mechanisms. The first refers to time-reversal symmetry breaking by magnetization of ferromagnets and tends to be strong because of the non-relativistic exchange origin(15). The second applies to crystals with broken inversion symmetry and tends to be comparatively weaker, as it originates from the relativistic spin-orbit coupling (SOC)(16-19). A recent theory work based on spin-symmetry classification has identified an unconventional magnetic phase, dubbed altermagnetic(20,21), that allows for LKSD without net magnetization and inversion-symmetry breaking. Here we provide the confirmation using photoemission spectroscopy and ab initio calculations. We identify two distinct unconventional mechanisms of LKSD generated by the altermagnetic phase of centrosymmetric MnTe with vanishing net magnetization(20-23). Our observation of the altermagnetic LKSD can have broad consequences in magnetism. It motivates exploration and exploitation of the unconventional nature of this magnetic phase in an extended family of materials, ranging from insulators and semiconductors to metals and superconductors(20,21), that have been either identified recently or perceived for many decades as conventional antiferromagnets(21,24,25).