Raman detection of hidden phonons assisted by atomic point defects in a two-dimensional semimetal

Hui Yuan, Xieyu Zhou, Yan Cao, Qi Bian, Zongyuan Zhang, Haigen Sun, Shaojian Li, Zhibin Shao, Jin Hu, Yanglin Zhu, Zhiqiang Mao, Wei Ji, Minghu Pan

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Abstract

Defects usually have an important role in tailoring various properties of two-dimensional (2D) materials. However, optical detection of defects, especially single-atom point defects, is very challenging in 2D layers. Here, we report our systematic studies on the Raman-activated defect vibrational modes in 2D semimetallic material by combining Raman spectroscopy, density functional theory (DFT) calculation and scanning tunneling microscopy (STM). We observed three common Raman-active vibrational modes located at 95 (A1g2), 228 (A1g1), and 304 cm−1 (B1g1) in ZrSiTe few-layers, consistent with our theoretical calculations. Moreover, a pronounced mode sitting at 131.7 cm−1 was found in the ZrSiTe monolayer. This mode fades out quickly in the bilayer (2L) and eventually disappears in 4L. The high-resolution STM images and DFT calculations suggest this mode to be an intralayer shear mode at the Brillouin zone boundary which is activated by atomic point defects, and STM-based inelastic tunneling spectrum further confirms the existence of such a defect mode. The appearance of such ‘forbidden’ modes in Raman spectra may pave an avenue for the optical characterization of single-atom point defects in metallic 2D layers.

Original languageEnglish (US)
Article number12
Journalnpj 2D Materials and Applications
Volume3
Issue number1
DOIs
StatePublished - Dec 1 2019

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All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Mechanical Engineering
  • Mechanics of Materials
  • Condensed Matter Physics
  • Chemistry(all)

Cite this

Yuan, H., Zhou, X., Cao, Y., Bian, Q., Zhang, Z., Sun, H., Li, S., Shao, Z., Hu, J., Zhu, Y., Mao, Z., Ji, W., & Pan, M. (2019). Raman detection of hidden phonons assisted by atomic point defects in a two-dimensional semimetal. npj 2D Materials and Applications, 3(1), [12]. https://doi.org/10.1038/s41699-019-0093-7