Mechanical Mode Imaging of a High-Q Hybrid hBN/Si<sub>3</sub>N<sub>4</sub> Resonator.

Jaeger, David; Fogliano, Francesco; Ruelle, Thibaud; Lafranca, Aris; Braakman, Floris; Poggio, Martino · Nano Lett · 2023

biomechanical · Level V

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Abstract

We image and characterize the mechanical modes of a 2D drum resonator made of hBN suspended over a high-stress Si<sub>3</sub>N<sub>4</sub> membrane. Our measurements demonstrate hybridization between various modes of the hBN resonator and those of the Si<sub>3</sub>N<sub>4</sub> membrane. The measured resonance frequencies and spatial profiles of the modes are consistent with finite-element simulations based on idealized geometry. Spectra of the thermal motion reveal that, depending on the degree of hybridization with modes of the heavier and higher-quality-factor Si<sub>3</sub>N<sub>4</sub> membrane, the quality factors and the motional mass of the hBN drum modes can be shifted by orders of magnitude. This effect could be exploited to engineer hybrid drum/membrane modes that combine the low motional mass of 2D materials with the high quality factor of Si<sub>3</sub>N<sub>4</sub> membranes for optomechanical or sensing applications.