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Determination of Crystal Axes in Semimetallic T′‐MoTe 2 by Polarized Raman Spectroscopy
Author(s) -
Wang Junyong,
Luo Xin,
Li Shisheng,
Verzhbitskiy Ivan,
Zhao Weijie,
Wang Shunfeng,
Quek Su Ying,
Eda Goki
Publication year - 2017
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201604799
Subject(s) - raman spectroscopy , materials science , polarization (electrochemistry) , zigzag , molecular vibration , spectroscopy , molecular physics , density functional theory , ray , crystal (programming language) , optics , single crystal , diffraction , nuclear magnetic resonance , physics , optoelectronics , geometry , chemistry , mathematics , quantum mechanics , computer science , programming language
Distorted octahedral T′ phase of MoTe 2 has recently attracted significant interest due to its predicted topological states and novel charge transport properties. Here, we report a nondestructive method for determining the crystal orientation of few‐layer T′‐MoTe 2 flakes by polarized Raman spectroscopy. The experimentally observed Raman modes are assigned to eigenmodes of vibrations predicted by density functional theory calculations. Polarized Raman measurements reveal four distinct types of angle‐dependent intensity variations. From group theory, it can be deduced that the intensity of the B g mode reaches a maximum in thex ¯ ( y z ) x configuration when the polarization vector of the incident light is either parallel or orthogonal to the metal–metal zigzag chain direction. The intensity variation of the B g mode cannot be used to unambiguously determine the crystal orientation. Using electron diffraction analysis, it is demonstrated that the intensity of the A g mode at around 162 cm −1 reaches a maximum when the polarization vector of the incident light is parallel to the metal–metal chain direction in thex ¯ ( y y ) x configuration. Furthermore, a simple method is proposed for identifying crystal orientation in nonpolarized Raman spectroscopy.