Energy and Nonextensive Entropy of Exciton-Polaron in Graphene under Electromagnetic Field

We evaluate the effects of electromagnetic radiation and dielectric screening of substrates SiC and SiO2 on the exciton-polaron state in a graphene monolayer. As in other two-dimensional (2D) materials deposited on polar substrates, the ground state energy was obtained by the Lee–Low–Pines variational method and the local disorder rate known as Tsallis entropy was calculated using Gibbs–Boltzmann statistics. Our results show that the ground state energy increases with the wave vector of the surface optical (SO) phonons, the strength of the Coulomb interaction and decreases with the frequency and the amplitude of the electromagnetic field. The entropy of the system decreases with the frequency and amplitude of the radiation and increases with the strength of the Coulomb interaction. These results suggest that the phonon wave vector, the dielectric screening of the substrates, the frequency, and the amplitude of the electromagnetic radiation are the key parameters useful to control the stability of exciton-polaron in graphene.