摘要
Kagome magnets with diverse topological quantum responses are crucial for next-generation topological engineering.The anisotropic magnetism and band evolution induced by ferromagnetic phase transition(FMPT)is reported in a newly discovered titanium-based kagome ferromagnet Sm Ti3Bi4,which features a distorted Ti kagome lattice and Sm atomic zig-zag chains.Temperature-dependent resistivity,heat capacity,and magnetic susceptibility reveal a ferromagnetic ordering temperature Tc of23.2 K.A large magnetic anisotropy,observed by applying the magnetic field along three crystallographic axes,identifies the b axis as the easy axis.Angle-resolved photoemission spectroscopy with first-principles calculations unveils the characteristic kagome motif,including the Dirac point at the Fermi level and multiple van Hove singularities.Notably,a band splitting and gap closing attributed to FMPT is observed,originating from the exchange coupling between Sm 4 f local moments and itinerant electrons of the kagome Ti atoms,as well as the time-reversal symmetry breaking induced by the long-range ferromagnetic order.Considering the large in-plane magnetization and the evolution of electronic structure under the influence of ferromagnetic ordering,such materials promise to be a new platform for exploring the intricate electronic properties and magnetic phases based on the kagome lattice.
基金
supported by the Synergetic Extreme Condition User Facility(SECUF)
the National Key Research and Development Program of China(Grant Nos.2022YFA1403800,2022YFA1403900,and 2018YFE0202600)
the National Natural Science Foundation of China(Grant Nos.U22A6005,51832010,11888101,11925408,11921004,and 12188101)
the Informatization Plan of the Chinese Academy of Sciences(Grant No.CASWX2021SF-0102)
the Strategic Priority Research Program of Chinese Academy of Sciences(Grant Nos.XDB33000000,and XDB28000000)
the“Dreamline”beamline of Shanghai Synchrotron Radiation Facility(SSRF)。
