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arXiv · 2110.08095

Second harmonic generation control in twisted bilayers of transition metal dichalcogenides

Ioannis Paradisanos·Andres Manuel Saiz Raven·Thierry Amand·Cedric Robert·Pierre Renucci·Kenji Watanabe·Takashi Taniguchi·Iann C. Gerber·Xavier Marie·Bernhard Urbaszek
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Abstract

The twist angle in transition metal dichalcogenide (TMD) heterobilayers is a compelling degree of freedom that determines electron correlations and the period of lateral confinement of moir\'e excitons. Here we perform polarization-resolved second harmonic generation (SHG) spectroscopy of MoS2/WSe2 heterostructures. We demonstrate that by choosing suitable laser energies the twist angle between two monolayers can be measured directly on the assembled heterostructure. We show that the amplitude and polarization of the SHG signal from the heterostructure are determined by the twist angle between the layers and exciton resonances at the SH energy. For heterostructures with close to zero twist angle, we observe changes of exciton resonance energies and the appearance of new resonances in the linear and non-linear susceptibilities.

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Ioannis Paradisanos, Andres Manuel Saiz Raven, Thierry Amand, Cedric Robert, Pierre Renucci, Kenji Watanabe, Takashi Taniguchi, Iann C. Gerber, Xavier Marie, Bernhard Urbaszek. 2021-10-15. Second harmonic generation control in twisted bilayers of transition metal dichalcogenides. https://doi.org/10.1103/physrevb.105.115420

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