We introduce a new family of 2D materials with unique structure and optoelectronic properties, namely, single-layer gold(I) halides (AuHals). We propose their stability as well as structural, electronic, and optical properties using first-principles calculations. The cleavage energy is found to be similar to that of graphene from graphite, indicating the possibility for mechanical exfoliation. We show that AuHals are stable and have tunable direct (AuBr) and indirect (AuI) band gaps depending on the number of layers. We discuss the possible origin of the giant spin–orbit coupling (SOC) induced conduction band splitting in terms of orbital-decomposed band structure to guide future investigations on the design of materials with highly effective SOC. Exceptionally high excitonic binding energy, high hole mobility, and tunable band gaps indicate that AuHals are promising candidates for optoelectronic devices with excellent performance.

中文翻译：

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二维金卤化物：具有巨大自旋轨道分裂和可调节光电特性的新型半导体

我们介绍了具有独特结构和光电特性的2D新材料系列，即单层卤化金（AuHals）。我们使用第一性原理计算来提出它们的稳定性以及结构，电子和光学性质。发现裂解能与来自石墨的石墨烯的裂解能相似，表明机械剥落的可能性。我们表明，AuHals是稳定的，并且具有可调整的直接（AuBr）和间接（AuI）带隙，具体取决于层数。我们根据轨道分解的能带结构来讨论巨自旋-轨道耦合（SOC）诱导的导带分裂的可能起源，以指导未来对具有高效SOC的材料设计的研究。高激子结合能，高空穴迁移率，