Journal of Infrared and Millimeter Waves, Volume. 41, Issue 2, 464(2022)

Near-field imaging of WTe2

Zhen-Bing DAI1,2, Guo-Yu LUO2, Yan HE2, Chong WANG3,4, Hu-Gen YAN3,4, and Zhi-Qiang LI2、*
Author Affiliations
  • 1Department of Physics,Sichuan Normal University,Chengdu 610066
  • 2College of Physics,Sichuan University,Chengdu 610065,China
  • 3State Key Laboratory of Applied Surface Physics,Fudan University,Shanghai 200438,China
  • 4Department of Physics,Fudan University,Shanghai 200438,China
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    Near-field optical response of WTe2 thin films was studied by using scanning near-field optical microscopy (SNOM) , we have observed bright fringes near the edge of the thin film sample and also a thickness dependence on optical contrast to the sample and substrate. To understand this behavior, first we obtain the dielectric function of WTe2 at room temperature by Drude-Lorentz model via fitting the infrared radiation (IR) reflectance and conductivity spectra, then the near-field ratio of thin film sample to the diamond substrate is calculated by the Finite-dipole model. The experimental result reveals that the behavior of the sample cannot be fully described by the bulk properties. We assume that a decoupled thin layer exists on the surface of the bulk. There are two possible explanations for the observation of the near-field patterns of bright outside fringes. Firstly, a hot-spot field may be produced between the tip and the sample edge due to the enhancement of the local electric field under the IR illumination, a similar behavior has been revealed in surface-metallic black phosphorus. Another probability is that the topological edge states of top decoupled monolayer WTe2 lead to an enhancement of the local optical conductivity. This work provides a reference from the optical research of topological materials in the future.

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    Zhen-Bing DAI, Guo-Yu LUO, Yan HE, Chong WANG, Hu-Gen YAN, Zhi-Qiang LI. Near-field imaging of WTe2[J]. Journal of Infrared and Millimeter Waves, 2022, 41(2): 464

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    Paper Information

    Category: Research Articles

    Received: Mar. 4, 2021

    Accepted: --

    Published Online: Jul. 8, 2022

    The Author Email: Zhi-Qiang LI (zhiqiangli@scu.edu.cn)

    DOI:10.11972/j.issn.1001-9014.2022.02.013

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