UC Berkeley

Fe₃GaTe₂, a recently discovered van der Waals ferromagnet, demonstrates intrinsic ferromagnetism above room temperature, necessitating a comprehensive investigation of the microscopic origins of its high Curie temperature (T_C). In this study, we reveal the electronic structure of Fe₃GaTe₂ in its ferromagnetic ground state using angle-resolved photoemission spectroscopy and density functional theory calculations. Our results establish a consistent correspondence between the measured band structure and theoretical calculations, underscoring the significant contributions of the Heisenberg exchange interaction (J_ex) and magnetic anisotropy energy to the development of the high-T_C ferromagnetic ordering in Fe₃GaTe₂. Intriguingly, we observe substantial modifications to these crucial driving factors through doping, which we attribute to alterations in multiple spin-splitting bands near the Fermi level. These findings provide valuable insights into the underlying electronic structure and its correlation with the emergence of high-T_C ferromagnetic ordering in Fe₃GaTe₂.