Identification of the Crystal Symmetry in 1T′ MoTe2 with Polarization-Resolved Second Harmonic Generation and Raman Scattering
Ryan Beams, Luiz Gustavo Cancado, Sergiy Krylyuk, Irina Kalish, Berc Kalanyan, Arunima Singh, Kamal Choudhary, Patrick Vora, Francesca M. Tavazza, Albert Davydov, Stephan J. Stranick
We study the crystal symmetry properties of few-layer 1T' MoTe2 using the polarization dependence of the second harmonic generation (SHG) and Raman scattering. Bulk 1T' MoTe2 is know to be inversion symmetric, however, we nd that the inversion symmetry is broken for finite crystals with even numbers of layers, resulting in strong SHG. Group theoretical analysis of the polarization dependence of the Raman signals allows for the assignment of all the Raman modes in 1T' MoTe2, which resolves a current disagreement in the literature.