PHONONIC FREQUENCY COMB GENERATION VIA 1:1 MODE COUPLING IN MoS2 2D NANOELECTROMECHANICAL RESONATORS

We report on the experimental demonstration of phononic frequency comb (PFC) generation in atomically thin molybdenum disulfide (MoS2) resonant nanoelectro-mechanical systems (NEMS) vibrating near similar to 50 MHz in the very high frequency (VHF) band. PFC patterns are generated by tuning two close-by resonances with a gate voltage (V-g), and driving them at an anticrossing point, where the two modes are coupled through 1:1 internal resonance. The PFC characteristics are tunable by varying RF driving voltage (v(drv)) and V-g. We find a threshold of PFC generation at v(drv) = 550mV and V-g = -6.4V, with relatively wide comb teeth spacing around 2.44 to 2.65MHz. At V-g = -7V, the comb teeth spacing is reduced to 0.63MHz, exhibiting strong tunability of PFC.

Automated summary

This study demonstrates the experimental generation of a phononic frequency comb in atomically thin MoS2 resonant NEMS. The spacing of the comb teeth can be tuned by voltage and driving, showing strong tunability.