Theoretical description of the Cyclotron Resonance in Dual-Gated Bilayer Graphene*

Recent experimental observations of cyclotron transitions involving the quasi-zero energy Landau-level (LL) octet in dual-gated graphene bilayer call for a theoretical description of the dependence on displacement (D) field. These transitions involve the positive and negative energy LLs above and below the octet indexed by N=2 and N=-2, respectively. We present results treating Coulomb interactions within Hartree-Fock approximation both within the octet and the index |N|=2 LLs. For D=0, good qualitative agreement is achieved for transitions at filling factors ν varying from -6 to 6. At ν=0 and small D, we find a LL polarized phase driven by particle-hole breaking terms where the 0th LL is below the Fermi energy, blocking 1→ 2 transitions. For intermediate D, a phase transition is predicted from this state to a layer polarized regime that is captured by the single-particle description. At ν=4 , strong agreement is found between theory and experiment for the D-dependence of the 1→ 2 transitions.