The Fano-like lineshape without interference in graphene symmetry-breaking structures

We demonstrate that the concepts in metal plasmonics cannot be totally used indiscriminately in graphene plasmonics. A typical Fano resonance for a metallic symmetry-breaking structure is simulated for graphene. Although a Fano-like extinction spectrum emerges, our analysis proves that the asymmetry is due to the intensity superposition of three plasmon modes instead of interference. The difference between graphene and metal plasmons comes from different contributions to the extinction, where the former is absorption instead of scattering. Furthermore, the asymmetric lineshape can be effectively tuned by changing not only the carrier mobility and Fermi energy of graphene, but also the geometry of the disk.