We perform classical molecular dynamics simulations to investigate theenhancement of the mass sensitivity and resonant frequency of graphenenanomechanical resonators that is achieved by driving them into the nonlinearoscillation regime. The mass sensitivity as measured by the resonant frequencyshift is found to triple if the actuation energy is about 2.5 times the initialkinetic energy of the nanoresonator. The mechanism underlying the enhanced masssensitivity is found to be the effective strain that is induced in thenanoresonator due to the nonlinear oscillations, where we obtain an analyticrelationship between the induced effective strain and the actuation energy thatis applied to the graphene nanoresonator. An important implication of this workis that there is no need for experimentalists to apply tensile strain to theresonators before actuation in order to enhance the mass sensitivity. Instead,enhanced mass sensitivity can be obtained by the far simpler technique ofactuating nonlinear oscillations of an existing graphene nanoresonator.
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