Phase engineering of 1T$'$ and 1T CrS2 and Cr2S3 by MOCVD
Haoyu Bai, Gareth R. M Tainton, Mauro Och, Max Rimmer, Indrajit Maity, Filippo Mione, Khagesh Tanwar, Rongsheng Cai, Joseph Parker, Kho Zhiquan, Ercin C Duran, Evan Tillotson, Sam Sullivan-Allsop, David Hopkinson, Siyuan Deng, Dan Bromley, Jack N. Carter-Gartside, Alex Vanstone, Sandrine Heutz, Will R. Branford, Efrén Navarro-Moratalla, Johannes C. Lischner, Sarah Haigh, Cecilia Mattevi
Published: 2025/9/9
Abstract
Layered Cr-chalcogenides compounds offer a rich range of phases with different magnetic properties some of which have been predicted only. Here we demonstrate a not yet reported crystal phase of CrS2 which is the distorted octahedral one (1T$'$) synthesized via metal-organic chemical vapour deposition (MOCVD). We achieved the tuneable synthesis of either 1T$'$ CrS2, or 1T CrS2. The phases were identified using polarized Raman spectroscopy, density functional perturbation theory (DFPT) and 4D-scanning transmission electron microscopy (STEM)-scanning electron diffraction. The phases of CrS2 were uniquely identified also in contrast with Cr2S3 which was synthesized and characterized by a Neel temperature of ~46 K. Using magneto-optic Kerr imaging, the 1T$'$ CrS2 crystals have soft ferromagnetic nature at low temperature, shedding light on the magnetic properties of this just predicated material. The 4DSTEM characterization reveals that the synthesis of the thermodynamically stable 1T$'$ phase occurs via a complex transformation process from the 1T to 1T$'$ resulting in a spatially correlated domain structure of differently oriented 1T$'$ crystals. Our MOCVD growth of complex and distorted phases of 2D CrS2 with long-range magnetic order paves the way for the scalable synthesis of 2D magnets for ultrathin magnetic memories for logic-in-memory applications and spintronics.