Resonances and kinks in the electromagnetic radiation absorption in a graphene ring

Abstract

An analytical expression of the absorption coefficient (AC) of the electromagnetic radiation in graphene rings placed in a magnetic field is obtained. Cases of a nondegenerate and a degenerate electron gas are considered. The dependences of the absorption coefficient on the frequency of the electromagnetic radiation and the magnitude of the magnetic field are investigated. It is shown that the absorption of the electromagnetic radiation has a resonant character. There are numerous peaks on the absorption curve due to the transitions between eigenstates of the electron spectrum. The AC curve contains kinks in the case of a degenerate gas.