We theoretically study the Floquet exciton condensation, which denotes the exciton condensation under an off-resonant circularly polarized light, in graphene bilayers. The polarized light greatly affects the gap function of the condensate as well as the related physical quantities, e.g., the condensate fraction and superfluid density both having maximal values as the photoillumination parameter varies. We find that the critical temperature rises fast and then slowly approaches a constant upon increasing the photoillumination parameter. The variation of the drag conductivity is obvious in a small range just below the critical temperature; furthermore, there exists competition between the photoillumination parameter and temperature in the gap function and drag conductivity. It is believed that these results can facilitate the experimental investigations of the Floquet exciton condensation in graphene bilayers.

• Received 15 May 2015
• Revised 27 July 2015

DOI:https://doi.org/10.1103/PhysRevB.92.085414