Unified Description of the Optical Phonon Modes in N-Layer MoTe2.

摘要: N-layer transition metal dichalcogenides provide a unique platform to investigate the evolution of physical properties between bulk (three-dimensional) and monolayer (quasi-two-dimensional) limits. Here, using high-resolution micro-Raman spectroscopy, we report unified experimental description Γ-point optical phonons in 2H-molybdenum ditelluride (MoTe2). We observe series N-dependent low-frequency interlayer shear breathing modes (below 40 cm–1, denoted LSM LBM) well-defined Davydov splittings mid-frequency (in range 100–200 iX oX), which solely involve displacements chalcogen atoms. In contrast, high-frequency 200–300 iMX oMX), arising from both atoms, exhibit considerably reduced splittings. The manifold phonon associated with in-plane out-of-plane are quantitatively described by force constant model, includi...