Double resonance Raman modes in monolayer and few-layer MoTe[subscript 2]
Name
PhysRevB.91.205415.pdf
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1.62 MB
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Checksum (MD5)
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Author(s)
Guo, Huaihong
Yang, Teng
Yamamoto, Mahito
Zhou, Lin
Ishikawa, Ryo
Ueno, Keiji
Tsukagoshi, Kazuhito
Zhang, Zhidong
Saito, Riichiro
Dresselhaus, Mildred
Date Issued
May 2015
Journal
Physical Review B
Publisher
American Physical Society
Citation
Guo, Huaihong, Teng Yang, Mahito Yamamoto, Lin Zhou, Ryo Ishikawa, Keiji Ueno, Kazuhito Tsukagoshi, Zhidong Zhang, Mildred S. Dresselhaus, and Riichiro Saito. “Double Resonance Raman Modes in Monolayer and Few-Layer MoTe[subscript 2].” Phys. Rev. B 91, no. 20 (May 2015). © 2015 American Physical Society
Version
Final published version
Abstract
We study the second-order Raman process of mono- and few-layer MoTe[subscript 2], by combining ab initio density functional perturbation calculations with experimental Raman spectroscopy using 532, 633, and 785 nm excitation lasers. The calculated electronic band structure and the density of states show that the resonance Raman process occurs at the M point in the Brillouin zone, where a strong optical absorption occurs due to a logarithmic Van Hove singularity of the electronic density of states. The double resonance Raman process with intervalley electron-phonon coupling connects two of the three inequivalent M points in the Brillouin zone, giving rise to second-order Raman peaks due to the M-point phonons. The calculated vibrational frequencies of the second-order Raman spectra agree with the observed laser-energy-dependent Raman shifts in the experiment.
MIT Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Research Laboratory of Electronics
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DOI of Published Version
https://doi.org/10.1103/PhysRevB.91.205415
