Tang Chi Sin, Yin Xinmao, Yang Ming, Wu Di, Wu Jing, Wong Lai Mun, Li Changjian, Tong Shi Wun, Chang Yung-Huang, Ouyang Fangping, Feng Yuan Ping, Wang Shi Jie, Chi Dongzhi, Breese Mark B H, Zhang Wenjing, Rusydi Andrivo, Wee Andrew T S
Department of Physics Faculty of Science National University of Singapore S12 Science Drive 3 Singapore 117551 Singapore.
NUS Graduate School for Integrative Sciences and Engineering National University of Singapore 21 Lower Kent Ridge Singapore 119077 Singapore.
Adv Sci (Weinh). 2020 Apr 16;7(10):1902726. doi: 10.1002/advs.201902726. eCollection 2020 May.
The quasimetallic 1T' phase 2D transition-metal dichalcogenides (TMDs) consist of 1D zigzag metal chains stacked periodically along a single axis. This gives rise to its prominent physical properties which promises the onset of novel physical phenomena and applications. Here, the in-plane electronic correlations are explored, and new mid-infrared plasmon excitations in 1T' phase monolayer WSe and MoS are observed using optical spectroscopies. Based on an extensive first-principles study which analyzes the charge dynamics across multiple axes of the atomic-layered systems, the collective charge excitations are found to disperse only along the direction perpendicular to the chains. Further analysis reveals that the interchain long-range coupling is responsible for the coherent 1D charge dynamics and the spin-orbit coupling affects the plasmon frequency. Detailed investigation of these charge collective modes in 2D-chained systems offers opportunities for novel device applications and has implications for the underlying mechanism that governs superconductivity in 2D TMD systems.
准金属性的1T'相二维过渡金属二硫属化物（TMDs）由沿单轴周期性堆叠的一维锯齿形金属链组成。这赋予了其显著的物理性质，有望引发新的物理现象和应用。在此，研究了面内电子关联，并使用光谱学方法在1T'相单层WSe₂和MoS₂中观测到了新的中红外等离子体激元激发。基于一项广泛的第一性原理研究，该研究分析了原子层系统多个轴上电荷的动力学，发现集体电荷激发仅沿垂直于链的方向色散。进一步分析表明，链间长程耦合负责相干的一维电荷动力学，而自旋轨道耦合影响等离子体激元频率。对二维链状系统中这些电荷集体模式的详细研究为新型器件应用提供了机会，并对二维TMD系统中超导性的潜在机制具有启示意义。
