Figure 4: High-pressure Raman spectroscopy and structural studies of 1T′-MoTe2.
(a) Pressure-dependent Raman signals for 1T′-MoTe2 at room temperature. The Raman spectra contain two characteristic peaks due to the Ag and Bg vibrational modes of the 1T′-MoTe2 structure. (b) Frequencies of Ag and Bg modes as function of pressure. The frequencies of both vibrational modes increase gradually and continuously as the pressure increases. (c) Pressure dependence of the monoclinic angle β obtained from SXRD studies. Isothermal compression at room temperature (red filled squares) shows increase of the monoclinic distortion with pressure, whereas reversible orthorhombic Td–monoclinic 1T′ transition is observed in isothermal compression (filled blue circles)/decompression (open blue circles) run at 135 K. The values of Raman frequencies in b and monoclinic angle in c at each pressure are average values obtained from several Raman spectra (XRD patterns) collected from different areas across the sample. The error bars for Raman frequencies in b and monoclinic angle in c due to s.d. are smaller than the symbols size.
