Repulsive and attractive Casimir forces between magnetodielectric slabs

The Casimir force between two parallel magnetodielectric slabs is investigated by means of Casimir–Lifshitz Theory. For two magnetodielectric slabs, one is permittivity-negative, while the other is permeability-negative in the real frequency space. Numerical results show that when the separation between these two slabs is small (or large), the Casimir force is repulsive, while for the intermediate separation, the Casimir force is attractive. As a consequence, there are two equilibria with zero Casimir force, and a repulsive–attractive–repulsive transition takes place with increasing the separation. Therefore, if the separation between two interacting slabs is manipulated in the small (or large) separation region, it is possible to overcome the stiction in micromechanical and nanomechanical systems.

► The Casimir force between two parallel magnetodielectric slabs is investigated.
► For the separation between two slabs is small (large), the Casimir force is repulsive.
► For the intermediate separation, the Casimir force is attractive.
► Two equilibria are formed at zero Casimir force with increasing separation.
► A repulsive–attractive–repulsive transition takes place with increasing separation.