First-principles study of electronic and magnetic properties of self-intercalated van der Waals magnet Cr${}_3$Ge${}_2$Te${}_6$

Abstract

Self-intercalated van der Waals magnets, characterized by self-intercalating native atoms into van der Waals layered structures with intrinsic magnetism, exhibit a variety of novel physical properties. Here, using first-principles calculations and Monte Carlo simulations, we report a self-intercalated van der Waals ferromagnet, Cr${}_3$Ge${}_2$Te${}_6$, which has a high Curie temperature of 492 K. We find that Cr${}_3$Ge${}_2$Te${}_6$ is nearly half-metallic with a spin polarization reaching up to 90.9%. Due to the ferromagnetism and strong spin-orbit coupling effect in Cr${}_3$Ge${}_2$Te${}_6$, a large anomalous Hall conductivity of 138 ${\Omega }^{-1}$ cm${}^{-1}$ and 305 ${\Omega }^{-1}$ cm${}^{-1}$ can be realized when its magnetization is along its magnetic easy axis and hard axis, respectively. By doping electrons (holes) into Cr${}_3$Ge${}_2$Te${}_6$, these anomalous Hall conductivities can be increased up to 318 ${\Omega }^{-1}$ cm${}^{-1}$ (648 ${\Omega }^{-1}$ cm${}^{-1}$). Interestingly, a 5-layer Cr${}_3$Ge${}_2$Te${}_6$ thin film retains the room-temperature ferromagnetism with a higher spin polarization and larger anomalous Hall conductivity. Our work demonstrates that Cr${}_3$Ge${}_2$Te${}_6$ is a novel room-temperature self-intercalated ferromagnet with high spin polarization and large anomalous Hall conductivity, offering great opportunities for designing nano-scale electronic devices.

16 pages, 6 figures, accepted by Chinese Physics B