Raman scattering in the transition-metal dichalcogenides of 1T'-MoTe2, T-d-MoTe2, and T-d-WTe2

Article

关键词: STRUCTURAL PHASE-TRANSITIONS;    DIRECT BANDGAP TRANSITION;    TOTAL-ENERGY CALCULATIONS;    GIANT MAGNETORESISTANCE;    ELECTRICAL-PROPERTIES;    TUNGSTEN-DITELLURIDE;    ELECTRONIC-STRUCTURE;    ULTRAHIGH MOBILITY;    VERSATILE TOOL;    LAYER MOS2;   

DOI  :  10.1103/PhysRevB.94.214105

来源: SCIE

【 摘 要 】

We comparably performed polarized Raman scattering studies of MoTe2 and WTe2. By rotating crystals to tune the angle between the principal axis of the crystals and the polarization of the incident/scattered light, we obtained the angle dependence of the intensities for all the observed modes, which is perfectly consistent with careful symmetry analysis. Combining these results with first-principles calculations, we clearly identified the observed phonon modes in the different phases of both crystals. Fifteen Raman-active phonon modes (10 A(g) + 5 B-g) in the high-symmetry phase 1T' -MoTe2 (300 K) were well assigned, and all the symmetry-allowed Raman modes (11 A(1) + 6 A(2)) in the low-symmetry phase T-d-MoTe2 (10 K) and 12 Raman phonons (8 A(1) + 4 A(2)) in T-d-WTe2 were observed and identified. The present paper provides basic information about the lattice dynamics in transition-metal dichalcogenides and may shed some light on the understanding of the extremely large magnetoresistance in this class of materials.

【 授权许可】

Free