Coexistence of topological nodal lines and Weyl nodes in a room-temperature half-metallic ferromagnet Cr3Si2Te6

Abstract

Topological half-metallic ferromagnets, featured by topologically nontrivial states and fully spin-polarized electronic carriers at the Fermi level, are fertile playgrounds for exploring topo-spintronic applications. However, such exotic compounds are still limited. Here, we systematically study a self-intercalated van der Waals magnet Cr3Si2Te6 by combining first-principles calculations and Monte Carlo simulations. We demonstrate that Cr3Si2Te6 is thermodynamically stable and a half-metallic ferromagnet with a Curie temperature up to 485 K, much above room temperature. Excitingly, we find that topological nodal lines and Weyl nodes coexist in the Cr3Si2Te6 bulk. Correspondingly, the Cr3Si2Te6 bulk exhibits a large anomalous Hall conductivity of 160 and 427 Ω−1 cm−1 when its magnetization is along its magnetic easy and hard axes, respectively. Moreover, its anomalous Hall conductivity can be increased to 374 (882) Ω−1 cm−1 by doping electrons (holes). Finally, we disclose that the 7-layer Cr3Si2Te6 thin film possesses half-metallic ferromagnetism with a high TC of 425 K, strong out-of-plane magnetic anisotropy energy, and large anomalous Hall conductivity. Our findings suggest that Cr3Si2Te6 is a room-temperature topological half-metallic ferromagnet, which could have promising prospects for practical applications in next-generation topo-spintronic and nanoscale electronic devices.