论文标题
外延单层Janus Sptse的合成
Synthesis of epitaxial monolayer Janus SPtSe
论文作者
论文摘要
Janus单层过渡金属二分法，其中两个chalcogen层具有不同的化学性质，将化学成分控制推向了范德华异质结构通常可以实现的。在这里，我们报告了这种新颖的Janus化合物SPTSE，预计将表现出强烈的Rashba旋转轨道耦合。我们通过在h $ _2 $ s气氛下通过硫化在PT（111）上的PTSE $ _2 $的单层PTSE $ _2 $转换来合成它。我们的原位和操作结构分析，具有放牧的发病率X射线衍射揭示了Janus合金形成的过程。生长的PTSE $ _2 $单层的结晶长距离顺序首先由于热退火而丢失。在存在硫源的情况下，随后的重结晶产生了高度有序的SPTSE合金，这是原始PTSE $ _2 $的ISO结构。使用角度分辨X射线光电子光谱法解决了化学成分，逐层逐层解决，表明SE-S By-S取代在最上方的Chalcogen层中有选择性地发生。
Janus single-layer transition metal dichalcogenides, in which the two chalcogen layers have a different chemical nature, push chemical composition control beyond what is usually achievable with van der Waals heterostructures. Here we report such a novel Janus compound, SPtSe, which is predicted to exhibit strong Rashba spin-orbit coupling. We synthetized it by conversion of a single-layer of PtSe$_2$ on Pt(111) via sulphurization under H$_2$S atmosphere. Our in situ and operando structural analysis with grazing incidence synchrotron X-ray diffraction reveals the process by which the Janus alloy forms. The crystalline long-range order of the as-grown PtSe$_2$ monolayer is first lost due to thermal annealing. A subsequent recrystallization in presence of a source of sulphur yields a highly ordered SPtSe alloy, which is iso-structural to the pristine PtSe$_2$. The chemical composition is resolved, layer-by-layer, using angle-resolved X-ray photoelectron spectroscopy, demonstrating that Se-by-S substitution occurs selectively in the topmost chalcogen layer.
