Tunable optical force on nonlinear graphene-wrapped nanoparticles

We investigate the optical force on the nonlinear graphene-wrapped nanoparticle by using the Maxwell's stress tensor together with the mean-field methods. We demonstrate the bistable optical force on the present nanoparticle which is due to the strong localized electric field in graphene at the plasmonic resonant wavelength. To further investigate the critical incident electric field for the up and down transistors, we find that the required switching-up threshold field is highly dependent on the permittivity of the nanoparticle, surrounding medium and Fermi energy instead of the relaxation time, with which one could achieve tunable nonlinear optical force on such graphene-wrapped nanoparticle to satisfy some practical purpose. Our results might supply an alternative way to manipulate nanoparticles and give the guideline for achieving the optical switching in nanoscale.