Tunable Stochastic\nState Switching in 2D MoS<sub>2</sub> Nanomechanical Resonators with\nNonlinear Mode Coupling and Internal\nResonance

Coupled nanomechanical resonators have unveiled fascinating\nphysical\nphenomena, including phonon–cavity coupling, coupled energy\ndecay pathway, avoided crossing, and internal resonance. Despite these\ndiscoveries, the mechanisms and control techniques of nonlinear mode\ncoupling phenomena with internal resonances require further exploration.\nHere, we report on the observation of stochastic switching between\nthe two resonance states with coupled 1:1 internal resonance, for\nresonant two-dimensional (2D) molybdenum disulfide (MoS<sub>2</sub>) nanoelectromechanical systems (NEMS), which is directly driven\nto the critical coupling regime without parametric pumping. We further\ndemonstrate that the probability of state switching is linearly tunable\nfrom ∼0% to ∼100% by varying the driving voltage. Furthermore,\nwe gradually increase the white noise amplitude and show that the\nprobability of obtaining the higher-energy state decreases, and the\nstochastic switching phenomenon eventually disappears. The results\nprovide insights into the dynamics of coupled NEMS resonators and\nopen up new possibilities for sensing and stochastic computing.