Leibniz-Institute for Solid State and Materials Research Dresden, Helmholtzstraße 20, 01069 Dresden, Germany.
Nanoscale. 2018 Oct 18;10(40):19014-19022. doi: 10.1039/c8nr04667k.
The 2D layered honeycomb magnet α-ruthenium(iii) chloride (α-RuCl3) is a promising candidate to realize a Kitaev spin model. As alteration of physical properties on the nanoscale is additionally intended, new synthesis approaches to obtain phase pure α-RuCl3 nanocrystals have been audited. Thermodynamic simulations of occurring gas phase equilibria were performed and optimization of synthesis conditions was achieved based on calculation results. Crystal growth succeeded via chemical vapor transport (CVT) in a temperature gradient of 973 K to 773 K on YSZ substrates. Single crystal sheets of high crystallinity with heights ≤30 nm were obtained via pure CVT. The crystal properties were characterized by means of optical and electron microscopy, AFM, SAED, micro-Raman and XPS proving their composition, morphology, crystallinity and phase-purity. A highlight of our study is the successful individualization of nanocrystals and the delamination of nanosheets on YSZ substrates down to the monolayer limit (≤1 nm) which was realized by means of substrate exfoliation and ultrasonication in a very reproducible way.
二维层状蜂窝状磁铁 α-钌(iii)氯化物 (α-RuCl3) 是实现 Kitaev 自旋模型的有前途的候选物。由于还打算在纳米尺度上改变物理性质，因此已经审查了获得相纯 α-RuCl3 纳米晶体的新合成方法。进行了发生气相平衡的热力学模拟，并根据计算结果优化了合成条件。在 YSZ 衬底上，通过化学气相传输 (CVT) 在 973 K 至 773 K 的温度梯度下成功进行了晶体生长。通过纯 CVT 获得了高度≤30nm 的高结晶度单晶片。通过光学和电子显微镜、AFM、SAED、微拉曼和 XPS 对晶体性质进行了表征，证明了其组成、形态、结晶度和相纯度。我们研究的一个亮点是成功地将纳米晶体和纳米片在 YSZ 衬底上进行个体化和分层，直至单层极限 (≤1nm)，这是通过衬底剥落和超声处理以非常可重复的方式实现的。
