发表机构
Technical University of Munich; Munich Center for Quantum Science and Technology (MCQST)（慕尼黑工业大学; 慕尼黑量子科学与技术中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过理论计算明确了MoS₂中CH$_\text{S}^-$缺陷的量子发射起源，发现相邻层可抑制声子边带，MoS₂/hBN异质结构模型与实验光致发光线形高度吻合。
AI 中文摘要
通过实验与理论的一致契合，确定二维材料中局域发射的微观起源仍具挑战性。近期STM/STS-STML测量将单层MoS₂/hBN(2L)/石墨烯中近1.8 eV的发射归因于带负电的CH$_\text{S}^-$缺陷，但该发射体的全面理论描述仍缺失。本文构建了该描述，系统研究了单层MoS₂、两种双层构型及MoS₂/hBN异质结构中CH$_\text{S}^-$的光物理性质：该缺陷在四种环境中保持相似的局部几何，且倾向于单重态基态，但其电子跃迁、零声子线、电声耦合、辐射寿命及跃迁偶极取向强烈依赖周围层；孤立单层模型表现出显著结构重组，产生宽且占主导的声子边带，与实验不符；添加相邻层（MoS₂或hBN）可大幅抑制声子边带，双层MoS₂中缺陷位置对其影响极小；尤其MoS₂/hBN模型产生弱声子边带，与实验光致发光线形高度吻合。研究首次实现CH$_\text{S}^-$发射的理论契合，进一步揭示相邻层对二维材料量子发射体的电子、振动及光学性质的决定作用。
英文摘要
Establishing the microscopic origin of localized emission in two-dimensional materials through consistent agreement between experiment and theory remains challenging. Recent STM/STS-STML measurements assigned an emission near 1.8 eV in monolayer MoS$_2$/hBN(2L)/graphene to the negatively charged CH$_\mathrm{S}^{-}$ defect. However, a comprehensive theoretical description of this emitter is still lacking. Here, we develop such a description and systematically investigate the photophysical properties of CH$_\mathrm{S}^{-}$ in monolayer MoS$_2$, two bilayer configurations, and a MoS$_2$/hBN heterostructure. The defect retains a similar local geometry and favors a singlet ground state in all four environments, whereas its electronic transition, zero-phonon line, electron-phonon coupling, radiative lifetime, and transition-dipole orientation depend strongly on the surrounding layers. The isolated-monolayer model exhibits substantial structural reorganization and produces a broad, dominant phonon sideband that is inconsistent with experiment. Adding an adjacent layer, either MoS$_2$ or hBN, substantially suppresses the phonon sideband, with only a minor dependence on the defect position in bilayer MoS$_2$. In particular, the MoS$_2$/hBN model yields a weak phonon sideband and closely reproduces the experimental photoluminescence lineshape. Our results thus provide the first theoretical agreement of CH$_\mathrm{S}^{-}$ emission and further reveal the role of adjacent layers in determining the electronic, vibronic, and optical properties of the quantum emitters in two-dimensional materials.
Comments11 pages, 4 figures
