Rare earth permanent magnets(REPMs)with both localized moments and itinerant conduction bands are not only important for fundamental research but also have significant technological applications.In particular,Sm2Co17i...Rare earth permanent magnets(REPMs)with both localized moments and itinerant conduction bands are not only important for fundamental research but also have significant technological applications.In particular,Sm2Co17is a prototypical hightemperture REPM,where the Co atoms form a kagome-honeycomb stacked lattice.Here we report the synthesis of epitaxial Sm_(2)Co_(17)films using molecular beam epitaxy and measurements of their momentum-resolved electronic structure from in-situ angle-resolved photoemission spectroscopy.Our results unveil two flat bands from Co 3d orbitals near the Fermi level(EF),one at ~-300 me V and another right at E_(F),which arise from orbital-selective destructive interference and strong electron correlations,respectively.In addition,our results reveal that Sm 4f states are far away from E_(F)(hence mostly localized)and exhibit an anomalous temperature dependence,caused by the 3d-4f magnetic coupling.Our findings provide direct spectroscopic insights to understand the strong uniaxial ferromagnetism in Sm_(2)Co_(17)(and REPMs alike).Our work also opens avenues to explore flatband physics near E_(F) and emergent phenomena in correlated kagome-honeycomb lattices.展开更多
基金supported by the National Key Research and Development Program of China(Grant Nos.2022YFA1402200,2023YFA1406303 and 2022YFA1403202)the National Natural Science Foundation of China(Grant Nos.12174331,12350710785 and 12274353)+4 种基金the Key Research and Development Program of Zhejiang Province,China(Grant No.2021C01002)the State Key Project of Zhejiang Province(Grant No.LZ22A040007)Zhejiang Provincial Natural Science Foundation of China(Grant Nos.LGG22E020006 and LDG25A040001)Centro Nacional de Desenvolvimento Científico e Tecnológico(CNPq)(Grant No.404312/2024-1)S?o Paulo Research Foundation(FAPESP)(Garnt No.2018/08845-3)。
文摘Rare earth permanent magnets(REPMs)with both localized moments and itinerant conduction bands are not only important for fundamental research but also have significant technological applications.In particular,Sm2Co17is a prototypical hightemperture REPM,where the Co atoms form a kagome-honeycomb stacked lattice.Here we report the synthesis of epitaxial Sm_(2)Co_(17)films using molecular beam epitaxy and measurements of their momentum-resolved electronic structure from in-situ angle-resolved photoemission spectroscopy.Our results unveil two flat bands from Co 3d orbitals near the Fermi level(EF),one at ~-300 me V and another right at E_(F),which arise from orbital-selective destructive interference and strong electron correlations,respectively.In addition,our results reveal that Sm 4f states are far away from E_(F)(hence mostly localized)and exhibit an anomalous temperature dependence,caused by the 3d-4f magnetic coupling.Our findings provide direct spectroscopic insights to understand the strong uniaxial ferromagnetism in Sm_(2)Co_(17)(and REPMs alike).Our work also opens avenues to explore flatband physics near E_(F) and emergent phenomena in correlated kagome-honeycomb lattices.
