Repulsion of polarized particles from two-dimensional materials

Abstract: Repulsion of nanoparticles, molecules and atoms from surfaces can have important applications in nanomechanical devices, microfluidics, optical manipulation and atom optics. Here, through the solution of a classical scattering problem, we show that a dipole source can experience a robust and strong repulsive force when its near-field interacts with a two-dimensional material that has a metallic character. As an example, the case of graphene is considered, showing that a broad bandwidth of repulsion can be obtained spanning the frequency range $0<\hbar\omega<(5/3)\mu_c$, where ${\mu}_c$ is the chemical potential of graphene, tuneable electrically or by chemical doping.