Ferromagnetic Van Der Waals Metal Fe₃GeTe₂: from Bulk to Atomically Thin Crystals
Jun Sung Kim1*
1Physics, Pohang University of Science and Technology, Korea
* presenting author:Jun Sung Kim, email:js.kim@postech.ac.kr
Atomically-thin crystals, recently realized using van der Waals (vdW) materials, provide a versatile platform for studying the stability and tunability of the correlated electron phases in reduced dimension. Here, we present the thickness dependence of the phase transition in the layered ternary metal chalcogenides, Fe₃GeTe₂, hosting the ferromagnetic (FM) phase at Tc ~ 220 K, highest among vdW ferromagnets. In ultrathin crystals, even with a thickness of five unit cells, we observed the stable FM ground state and large anomalous Hall effect. The clear correlation between Tc and the in-plane saturation field demonstrate that the uniaxial magnetic anisotropy is essential for stabilizing the FM phase, confirming two-dimensional nature of ferromagnetism.

Keywords: van der Waals material, ferromagnetism