Figure 1

Schematic diagram and experimental setup of coherent phonon oscillation in few layer and bulk MoS₂ (a) Schematic diagram of generation and detection of the longitude acoustic coherent phonons in the MoS₂ crystal. (b) The crystal structure of MoS₂. It contains two unit cells of MoS₂ monolayer in the diagram. (c) Schematic diagram of the confined mode in the thin layers MoS₂ which is standing waves of in phase atomic oscillations. As the case in this figure, one surface of the film is free (zero-stress boundary condition) and the other is in contact with the substrate, which gives an approximately zero-displacement boundary condition. (d) Schematic diagram of experimental setup.