Gigahertz multimode vibrations in graphene and MoS₂ nanomechanical resonators at room temperature

Probing and understanding ultrahigh-frequency/gigahertz (UHF/GHz) vibrations in atomic layer nanomechanical resonators holds strong promise for fundamental studies and technological applications, such as sensing, signal processing, and quantum engineering. However, accessing GHz flexural-mode resonances in such devices at room temperature has been challenging. Here, we demonstrate the first measurement of GHz flexural vibrations in graphene and molybdenum disulfide (MoS₂) resonators at room temperature, achieving multimode resonances (f_m,n) up to ~1.09 GHz and quality factors (Q_m,n) up to ~5400 in multilayer MoS₂ resonators, and f_m,n up to ~1.03 GHz with high Q_m,n ~4500 in few-layer graphene resonators. Both fs and Qs are the highest among reported atomic layer nanomechanical resonators at room temperature, yielding f_m,n × Q_m,n ~ 5 × 10¹² Hz. We also reveal a Q scaling law with higher modes, which favors detecting GHz resonances. This study will enable exploiting multiple modes in atomic layer resonators toward resonant sensing and transduction functions at UHF/GHz.