Intermode coupling in nanomechanical resonators as a key for tuning the effective nonlinearity

Nonlinearity is a critical property of nanomechanical resonators, and methods for its control are in high demand, especially as it can enrich device dynamics and extend functionality. The authors show that the coupling between flexural and torsional modes in a cantilever-like nanomechanical resonator makes it possible to tune the effective nonlinearity displayed by each mode, over a wide range in situ. The intermode nonlinearity seems to be much stronger than the intramode one, in flat resonators of high width-to-thickness ratio. This approach might augment multimode atomic force microscopy, nanomechanical quantum nondemolition measurements, phononic frequency-comb generation, and more.