Dynamical actuation of graphene MEMS under the influence of Casimir forces ^(a)

Abstract We investigate the influence of the Casimir force on the dynamic behavior of a microdevice made of two freestanding parallel graphene sheets, and examine the dependence of its efficiency on the graphene band gap around the Dirac point. Bifurcation and phase diagrams are used to analyze device actuation due to small changes in the graphene band structure by the presence of defects, and compare it to the performance of a SiC-based microsystem. It is found that an increase of the mass gap parameter of graphene leads to an increment of stable operation, while the latter decreases by switching to SiC-based devices. For the non-conservative microsystem, the Melnikov function method and Poincaré diagram are used to investigate how changes in the graphene band structure result in chaotic motion. It is found that a small change around the Dirac point can significantly alter the threshold condition for chaotic behavior where the possibility to occur increases with decreasing of the mass gap parameter.