Magnetic ground state and electron-doping tuning of Curie temperature in Fe3GeTe2: First-principles studies

Intrinsic magnetic van der Waals (vdW) materials have attracted much attention, especially Fe3GeTe2 (FGT), which exhibits highly tunable properties. However, despite vast efforts, there are still several challenging issues to be resolved. Here, using a first-principles linear-response approach, we carry out a comprehensive investigation of both bulk and monolayer FGT. We find that although the magnetic exchange interactions in FGT are frustrated, our Monte Carlo simulations agree with the total energy calculations, confirming that the ground state of bulk FGT is indeed ferromagnetic (FM). We confirm that the Curie temperature raising under electron doping is an intrinsic effect. A tiny electron doping reduces the magnetic frustration, resulting in a significant increase of the Curie temperature. We also calculate the spin-wave dispersion, and find a small spin gap as well as a nearly flat band in the magnon spectra. These features can be compared with the future neutron scattering measurement to finally clarify the microscopic magnetic mechanism in these two-dimensional family materials.

Automated summary

Research on Fe3GeTe2 (FGT) revealed highly tunable properties and intrinsic effects of electron doping, leading to significant increases in the Curie temperature. Spin-wave dispersion analysis showed small spin gap and almost flat band, suggesting potential for clarifying the microscopic magnetic mechanisms in two-dimensional material families.