Room-temperature intrinsic ferromagnetism in epitaxial CrTe<sub>2</sub> ultrathin films.

Zhang, Xiaoqian; Lu, Qiangsheng; Liu, Wenqing; Niu, Wei; Sun, Jiabao; Cook, Jacob; Vaninger, Mitchel; Miceli, Paul F et al. · Nat Commun · 2021

basic_science · Level V

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Abstract

While the discovery of two-dimensional (2D) magnets opens the door for fundamental physics and next-generation spintronics, it is technically challenging to achieve the room-temperature ferromagnetic (FM) order in a way compatible with potential device applications. Here, we report the growth and properties of single- and few-layer CrTe<sub>2</sub>, a van der Waals (vdW) material, on bilayer graphene by molecular beam epitaxy (MBE). Intrinsic ferromagnetism with a Curie temperature (T<sub>C</sub>) up to 300 K, an atomic magnetic moment of ~0.21 [Formula: see text]/Cr and perpendicular magnetic anisotropy (PMA) constant (K<sub>u</sub>) of 4.89 × 10<sup>5</sup> erg/cm<sup>3</sup> at room temperature in these few-monolayer films have been unambiguously evidenced by superconducting quantum interference device and X-ray magnetic circular dichroism. This intrinsic ferromagnetism has also been identified by the splitting of majority and minority band dispersions with ~0.2 eV at Г point using angle-resolved photoemission spectroscopy. The FM order is preserved with the film thickness down to a monolayer (T<sub>C</sub> ~ 200 K), benefiting from the strong PMA and weak interlayer coupling. The successful MBE growth of 2D FM CrTe<sub>2</sub> films with room-temperature ferromagnetism opens a new avenue for developing large-scale 2D magnet-based spintronics devices.