Laser Assisted Dirac Electron in a Magnetized Annulus

Abstract

We study the behaviour of a charge bound on a graphene annulus under the assumption that the particle can be treated as a massless Dirac electron. The eigenstates and relative energy are found in closed analytical form. Subsequently, we consider a large annulus with radius ρ∈[5000,10,000]a0 in the presence of a static magnetic field orthogonal to its plane and again the eigenstates and eigenenergies of the Dirac electron are found in both analytical and numerical form. The possibility of designing filiform currents by controlling the orbital angular momentum and the magnetic field is shown. The currents can be of interest in optoelectronic devices that are controlled by electromagnetic radiation. Moreover, a small radial force acts upon the annulus with a stretching effect. A linearly polarized electromagnetic field propagating in the orthogonal direction is added; the time evolution of the operators show that the acceleration of the electron is proportional to the rate of change of the spin of the particle.

Large Angular Momentum States in a Graphene Film

“…Actually, the energy of the electrons increases by decreasing the radius ρ 1 and this outcome can be exploited if wanted. As a side effect, it can be noticed that a stretching force is exerted by the charge on the disk [36] wich increases with the confinement and, consequently, with the magnetic field. Such a stretching may become detectable in the near future.…”

“…The calculations to find the expressions for the operators and to obtain their equation of motion require quite an amount of algebra and may be rather long. In what follows, we confine ourselves to outlining the significant steps and the interested reader may find details in [5,36]. Thus, after long but straightforward use of commutator algebra, the equation…”

“…Actually, it is a straightforward task to check, by direct calculations, that ψ ˙(ρ, φ) is not eigenstate of σ 3 . In order to obtain the form of the equation for the radial parts, many tedious steps are required [36]; the result is…”

Dynamic clock generator and memory mass device using a quantum ring driven by three-color laser fields

“…In this case, the electron spin can be exploited and fast logic gates can be investigated. 10,11 A point of interest lies in large graphene annuli 7 where the peculiar dispersion properties of massless Dirac electrons can be utilised to create localised filiform currents of large angular momentum apt to store many bits of information.…”