A metastable trigonal phase, existing only as small patches on a chemically exfoliated few-layered, thermodynamically stable $1H$ phase of $\mathrm{Mo}{\mathrm{S}}_2$, is believed to critically influence the properties of $\mathrm{Mo}{\mathrm{S}}_2$-based devices. The electronic structure of this metastable phase is little understood in the absence of a direct experimental investigation of its electronic properties, complicated further by conflicting claims from theoretical investigations. We address this issue by investigating the electronic structure of this minority phase in chemically exfoliated $\mathrm{Mo}{\mathrm{S}}_2$ few-layered systems by enhancing its contributions with the use of highly spatially resolved ($\le 120$ nm resolution) photoemission spectroscopy and Raman spectroscopy in conjunction with state-of-the-art electronic structure calculations. Based on these results, we establish that the ground state of this phase, arrived at by the chemical exfoliation of $\mathrm{Mo}{\mathrm{S}}_2$ using the usual Li intercalation technique, is a small gap ($\sim 90\pm 40\mathrm{meV}$) semiconductor in contrast to most claims in the literature; we also identify the specific trigonal structure it has among many suggested ones.

中文翻译：

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化学剥落的MoS2层：占主导地位的三角亚稳相的半导体性质的光谱证据

亚稳态三角相，仅在化学剥落的几层，热力学稳定的小片上存在 $\mathrm{1个}H$ 的阶段 $莫{\mathrm{小号}}_{\mathrm{2个}}$，据信会严重影响 $莫{\mathrm{小号}}_{\mathrm{2个}}$基于设备。在缺乏对它的电子性质的直接实验研究的情况下，对该亚稳相的电子结构了解甚少，而理论研究的矛盾主张使这一情况进一步复杂化。我们通过研究这种化学剥落的少数相的电子结构来解决这个问题$莫{\mathrm{小号}}_{\mathrm{2个}}$ 通过使用高度空间分辨（$\le 120$纳米级分辨率），光发射光谱和拉曼光谱以及最新的电子结构计算。根据这些结果，我们确定该相的基态是通过化学剥落而获得的。$莫{\mathrm{小号}}_{\mathrm{2个}}$ 使用通常的Li插层技术，差距很小（$〜90\pm 40\mathrm{病毒}$）半导体与文献中的大多数主张相反；我们还会在许多建议的结构中找出其特定的三角结构。