Two-dimensional (2D) transition metal dichalcogenides (TMDCs) have been extensively studied. Among them, vanadium dichalcogenides, a unique metallic family of the TMDCs, have been considered as potential room temperature ferromagnetic materials at the monolayer scale. However, further progress has been hampered by the difficulties growing monolayer and the challenges making high-quality single crystalline VSe₂, free from artificial factors. Here, we report high-quality octahedral 1T-VSe₂ single crystals grown by chemical vapor transport. Spectroscopic analyses identified that as-grown VSe₂ crystals were a single phase of VSe₂ and highly oriented along the (00l) plane. High-resolution scanning transmission electron microscopy verified that as-grown VSe₂ crystals not only had single crystalline nature, the octahedral 1T phase, and AAA stacking order in atomistic real space, but also supported valuable lattice information that differed from the predicted values of the previous calculation model. Mechanical exfoliation allowed our VSe₂ crystals to turn into large-sized VSe₂ flakes with various thicknesses. With in-depth structural analyses, our findings provide insight into further research of the fundamental calculation model and the crystallographic tailoring for intrinsic room-temperature 2D ferromagnetic materials.

中文翻译：

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化学蒸汽传输生长的1T-VSe ₂单晶的深度结构表征

二维（2D）过渡金属二卤化物（TMDC）已被广泛研究。其中，二氢钒化钒（TMDC的独特金属家族）已被视为单层规模的潜在室温铁磁材料。但是，单层生长的困难和制造无人为因素的高质量单晶VSe ₂的挑战阻碍了进一步的发展。在这里，我们报告通过化学气相传输生长的高质量八面体1T-VSe ₂单晶。分光分析鉴定，作为生长VSE _2个晶体是VSE的单相₂和沿（00高度取向升）平面。高分辨率扫描透射电子显微镜证实，生长中的VSe ₂晶体不仅具有单晶性质，八面体1T相和原子真实空间中的AAA堆积顺序，而且还支持了与晶格的预测值不同的有价值的晶格信息。先前的计算模型。机械剥离使我们的VSe ₂晶体变成了各种厚度的大尺寸VSe ₂薄片。通过深入的结构分析，我们的发现为深入研究基本计算模型以及固有室温2D铁磁材料的晶体学剪裁提供了见识。