Graphene quantum dot with Maxwell fish eye potential energy profile is studied. A quasiclassical approximation used given that a slowly varying function of coordinates. Near the zero spectrum electron macroscopically degenerates. All trajectories are closed circles classified by angular momentum and an additional integral motion. Provided complete filling lower Dirac zone, universal value for H...

Graphene has recently emerged as an important material for optoelectronic applications owing to its unique properties. Here, we show that graphene is also appealing the development of THz quantum optics when used dots. In particular, demonstrate a large electric dipole length d≈230 nm in single dot, corresponding amplitude ≈10μeV field. This estimate done using transport measurements under cohe...

Topologically protected helical states at a mass-inverted quantum dot in graphene are studied by analyzing both tight-binding and kernel polynomial method calculations. The is introduced considering heterojunction between two different mass domains, which similar to the domain wall bilayer graphene. numerical results show emergent metallic channels across gap when signs of terms opposite. eigen...