Measuring Valley Susceptibility of Transition Metal Dichalcogenides with Second-harmonic Spectroscopy

ORAL

Abstract

Polarization-resolved (PR) photoluminescence (PL) [1] and Kerr rotation (KR) [2] are commonly used to probe the degree of valley polarization (VP) of transition metal dichalcogenides (TMDs). Recently, second-harmonic (SH) generation was proposed to also probe VP [3], with the advantage over PL and KR of not requiring the material to have a bandgap or strong spin-orbital coupling, and thus extending VP measurements to other materials such as graphene.

In this work, we have develop a technique that uses a single laser beam prepared in a polarization state that simultaneously creates VP and pumps the SH process. By increasing the ellipticity of this pump beam, which translates into a larger VP in the sample, we observed an additional SH signal due to the VP, in good agreement with our theoretical model. Based on a transient analysis within the duration of the laser pulse, our model confirms SH susceptibility induced by VP to be directly proportional to the degree of VP, with the effect an order of magnitude higher for a quasi-resonant VP pump when compared to the off-resonant case.

[1] Nat. Nanotechnol. 7, 490 (2012), Nat. Nanotechnol. 7, 494 (2012).
[2] Phys. Rev. B 90, 161302(R) (2014), Nat. Commun. 6, 8963 (2015).
[3] 2D Mater. 4, 21027 (2017).

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Presenters

  • Yi Wei Ho

    NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore

Authors

  • Yi Wei Ho

    NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore

  • Henrique Guimaraes Rosa

    Centre for Advanced 2D Materials, National University of Singapore

  • Ivan Verzhbitskiy

    Centre for Advanced 2D Materials, National University of Singapore

  • Manuel Jose Ferreira de Lima Rodigues

    Center of Physics and Department of Physics, Universidade do Minho

  • Takashi Taniguchi

    National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305 0044, Japan, National Institute for Materials Science, Advanced Materials Laboratory, National Institute for Materials Science, , 1-1 Namiki, Tsukuba 305-0044, Japan, National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, National Institute of Materials Science, NIMS, Japan, Advanced Materials Laboratory, NIMS, National Institute for Materials Science, Tsukuba, Japan, Advanced Materials Laboratory, National Institute for Materials Science, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0044, Japan, National Institute for Materials Science (NIMS), NIMS Tsukuba, NIMS, National Institute for Material Science, National Institute for Materials Science, Japan, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Japan, National Institute for Materials Science , Japan, Advanced Materials Laboratory, National Institute for Materials Science, Japan, Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan, National Institute for Materials Science, Tsukuba, Ibaraki 305- 0044, Japan, National Institute for Material Science - Japan, National Institute for Materials Science, Namiki Tsukuba Ibaraki, Japan, National Institute of Material Science, Advanced Material Lab, NIMS, Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Japan, Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Ibaraki, Japan, National Institute for Materials Science, Tsukuba, 1-1 Namiki, Tsukuba, National Institute for Materials Science, NIMS/Tsukuba, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 Japan, National Institute for Materials Science, Namiki, 305-0044, Japan, National Institute for Material Science, Japan, Advanced Materials Laboratory, NIMS, Japan, Advanced Materials Labaratory, National Institute for Materials Science, National Institute of Material Science, 1-1 Namiki, Tsukuba, Ibaraki 205-0044, Japan, National Institute of Materials Science, Japan

  • Kenji Watanabe

    National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305 0044, Japan, Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, National Institute for Materials Science, Advanced Materials Laboratory, National Institute for Materials Science, , 1-1 Namiki, Tsukuba 305-0044, Japan, National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, National Institute of Materials Science, NIMS, Japan, Advanced Materials Laboratory, NIMS, National Institute for Materials Science, Tsukuba, Japan, National Institute for Materials Science, Japan, Advanced Materials Laboratory, National Institute for Materials Science, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0044, Japan, National Institute for Materials Science (NIMS), NIMS Tsukuba, National Institute for Materials Science (Japan), NIMS, National Institute for Material Science, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Japan, National Institute for Materials Science , Japan, National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan., Advanced Materials Laboratory, National Institute for Materials Science, Japan, Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan, National Institute for Materials Science, Tsukuba, Ibaraki 305- 0044, Japan, National Institute for Material Science - Japan, National Institute for Materials Science, Namiki Tsukuba Ibaraki, Japan, National Institute of Material Science, Advanced Material Lab, NIMS, Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Japan, Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Ibaraki, Japan, National Institute for Materials Science, Tsukuba, 1-1 Namiki, Tsukuba, National Institute for Materials Science, NIMS/Tsukuba, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 Japan, National Institute for Materials Science, Namiki, 305-0044, Japan, National Institute for Material Science, Japan, Advanced Materials Laboratory, NIMS, Japan, Columbia University, Advanced Materials Labaratory, National Institute for Materials Science, National Institute of Material Science, 1-1 Namiki, Tsukuba, Ibaraki 205-0044, Japan, National Institute of Materials Science, Japan

  • Goki Eda

    Centre for Advanced 2D Materials, National University of Singapore, Department of Physics, National University of Singapore

  • Vitor Pereira

    Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546, National University of Singapore, Department of Physics, National University of Singapore, Centre for Advanced 2D Materials, National University of Singapore

  • José Carlos Viana-Gomes

    Centre for Advanced 2D Materials, National University of Singapore