Attractive-repulsive transition of the Casimir force between anisotropic plates

The quantized surface mode technique is used to calculate the Casimir force between two parallel anisotropic metamaterial plates with in-plan optical axes, and the main concern is focused on the possible attractive-repulsive transition of the force. The result shows that if the electric and magnetic responses of the plates are frequency dependent, the Casimir force between them is attractive when the separation is small and is able to become repulsive as the separation increases. Moreover, the polarity of the Casimir force depends on the degree of anisotropy near the zero-force position.