The van der Waals Kitaev magnet α-RuCl₃ has recently garnered considerable attention due to its possible realization of topological spin liquids. Combining Raman spectroscopy with numerical calculations, we report here the thickness dependence of electronic structure and ensuing low-energy excitations for exfoliated α-RuCl₃. We observe two pronounced peaks at A1 = 249 meV and A2 = 454 meV, which are assigned to single and double spin-orbit (SO) excitons, respectively. Our numerical calculations support this interpretation by reproducing their spectral energy and shape with the electronic parameters: SO coupling λ = 140 meV, Hund’s coupling J_H = 350 meV, and on-site Coulomb interaction U = 2.35 eV. The multiple SO excitons persist down to a single layer, whereas their peaks shift slightly to lower energy. For frequencies below 350 cm⁻¹, both a magnetic continuum and phonons show noticeable thickness dependence. These results demonstrate that a SO entangled j_eff = 1/2 picture remains valid in a monolayer limit despite the presence of lattice distortions.

范德瓦尔斯Kitaev磁铁α-的RuCl面包车₃最近获取了相当大的关注，因为它可以实现拓扑自旋液体。组合拉曼光谱与数值计算中，我们在这里报告的电子结构和用于剥离的α-的RuCl随后低能量激发的厚度依赖性₃。我们在A1 = 249 meV和A2 = 454 meV处观察到两个明显的峰，分别分配给单和双自旋轨道（SO）激子。我们的数值计算通过使用电子参数重现其光谱能量和形状来支持这种解释：SO耦合λ  = 140 meV，Hund耦合J _H  = 350 meV，以及现场库仑相互作用U = 2.35 eV。多个SO激子持续下降到单层，而它们的峰会稍微移动以降低能量。对于低于350 cm ^-1的频率，连续磁和声子都显示出明显的厚度依赖性。这些结果表明， 尽管存在晶格畸变，但SO纠缠的j _eff = 1/2图片在单层限制中仍然有效。