标题： 金属支撑的单层MoS$_2$的表面敏感拉曼响应 显示英文标题

标题： Surface Sensitive Raman Response of Metal-Supported Monolayer MoS$_2$

摘要： 单层（ML）MoS$_2$的拉曼光谱受金属相互作用的影响显著。在这项工作中，我们通过实验和理论相结合的方法研究了负载在 Ag(111) 和 Ag(110) 表面上的 ML-MoS$_2$。MoS$_2$层通过脉冲激光沉积直接生长在原子级清洁的 Ag(111) 和 Ag(110) 表面上，随后在超高真空条件下进行原位热退火。通过扫描隧道显微镜对这两个系统的形貌和结构进行了原位表征，提供了有关 MoS$_2$晶格与底层表面之间关系的原子尺度信息。拉曼光谱揭示了两种 MoS$_2$-金属界面之间的差异，特别是在非平面$A'_1$振动模式的行为方面，该模式在 Ag(110) 上分裂成两个贡献。 金属引起的效应在MoS$_2$振动模式上进一步显现，通过将MoS$_2$转移到一个更惰性的基底（SiO$_2$/Si）上，其中MoS$_2$的拉曼响应表现出更类似于“自由悬浮”的行为。 实验数据得到了从头计算振动模式的支持，这些计算提供了界面性质（如应变和面外畸变）影响的见解。 我们的结果突显了与金属相互作用对MoS$_2$振动特性的影响，并显示了MoS$_2$拉曼模式对支撑金属表面结构的高度敏感性。 显示英文摘要

摘要： The Raman spectrum of monolayer (ML) MoS$_2$ is remarkably affected by the interaction with metals. In this work we studied ML-MoS$_2$ supported by the Ag(111) and Ag(110) surfaces by using a combined experimental and theoretical approach. The MoS$_2$ layer was directly grown on atomically clean Ag(111) and Ag(110) surfaces by pulsed laser deposition, followed by in-situ thermal annealing under ultra-high vacuum conditions. The morphology and structure of the two systems were characterized in-situ by scanning tunneling microscopy, providing atomic-scale information on the relation between the MoS$_2$ lattice and the underlying surface. Raman spectroscopy revealed differences between the two MoS$_2$-metal interfaces, especially concerning the behavior of the out-of-plane $A'_1$ vibrational mode, which splits into two contributions on Ag(110). The metal-induced effects on MoS$_2$ vibrational modes are further evidenced by transferring MoS$_2$ onto a more inert substrate (SiO$_2$/Si), where the MoS$_2$ Raman response displays a more ``freestanding-like'' behavior. The experimental data were interpreted with the support of ab-initio calculations of the vibrational modes, which provided insight into the effect of interface properties, such as strain and out-of-plane distortion. Our results highlight the influence of the interaction with metals on MoS$_2$ vibrational properties, and show the high sensitivity of MoS$_2$ Raman modes to the surface structure of the supporting metal.