Theoretical Study On The Enhancement Of Casimir Effects By Hyperbolic Surface Polaritons

The Casimir effect is a phenomenon manifested by quantum effect on macroscopic objects.The common Casimir effects include Casimir force,Casimir torque and Casimir friction.These strange phenomena have attracted wide attention.Graphene is a two-dimensional material composed of carbon atoms.It has excellent mechanical,electronic and optical properties.It is particularly important that it can support surface plasmons（SPs）in the terahertz to infrared frequency ranges.Bismuth triselenide（Bi₂Se₃）,as one of the representative topological insulators,has novel surface electronic states and bulk optical responses.Bi₂Se₃is also an optical material with hyperbolic dispersion relation,which can support highly oriented hyperbolic phonon polaritons（HPPs）in the terahertz range.Hyperbolic materials can support the propagation of evanescent electromagnetic waves in their interior,which can greatly improve the local electromagnetic state density near their surface.Therefore,we study the regulation of Casimir friction by Bi₂Se₃.In this paper,we study the Casimir friction in the environment of graphene-based hyperbolic materials,including graphene covered with undoped Bi₂Se₃and doped Bi₂Se₃.In the graphene/Bi₂Se₃composite structure,the Casimir friction can be enhanced by more than one order of magnitude compared to the undoped Bi₂Se₃due to the Bi₂Se₃-supported HPPs coupled to the graphene-supported SPs,which can form surface plasmon-phonon polaritons（SPPPs）.Due to the contribution of the unusual electronic surface states,the friction coefficient between doped Bi₂Se₃can even be larger than that between graphene covering undoped Bi₂Se₃at the appropriate chemical potential.In addition,we have investigated the non-dissipation axial Casimir force（ACF）of nanoparticles rotating near the graphene-based hyperbolic metasurfaces.It is found that when the rotation direction of the nanoparticle is parallel to the hyperbolic metasurface and the deflection Angle is an integer multiple ofπ/4,the numerical results show that the ACF on the rotating nanoparticle is the largest.The influence of graphene chemical potential and graphene band width on the ACF is also studied in detail.It is found that the ACF increases with the increase of chemical potential.However,the ACF first increases and then decreases as the graphene strip width increases.The research in this paper not only extends the application of hyperbolic metamaterial and hyperbolic metasurfaces to the field of Casimir effect,but also provides a new method for the regulation of Casimir effect.