Casimir force tuning in 2D materials: effect of rotation in phosphorene

Abstract

We theoretically examine the Casimir force with Lifshitz theory for two-dimensional media: graphene and phosphorene. We calculate the Casimir force for three different configurations: (a) phosphorene-graphene, (b) phosphorene-phosphorene (with rotation), and (c) a system composed of gold and a two-dimensional material (graphene or phosphorene). According to our calculations, we have determined that systems consisting solely of two-dimensional media can reduce the magnitude of the Casimir force by half or more, in comparison to systems composed of two-dimensional material and gold. The results show that in phosphorene configurations, high frequencies play a dominant role in contributing to the Casimir force, allowing greater force magnitudes for low interlayer distances compared to systems composed of gold or graphene. Our calculations also show that, as a result of the anisotropy of the phosphorene layers, it is possible to design a mechanical modulator with only two phosphorene layers by considering a relative rotation between them by an angle θ. In this regard, the anisotropy of phosphorene and the modulation of the separation between the phosphorene layers make it possible to tune the amplitude of Casimir force. The proposed configurations could lead to the development of nanotechnology applications incorporating 2D materials into their structures.