The Effects Of The Magnetic Barrier On The Bound State And Scattering Of Graphene Quantum Dots

The graphene quantum dot is one of the quasi-zero dimensional nanometer materials whose special strcuture leads to the exciton and quantumsize-effect.In addition,the properties of the graphene quantum dot are codetermined by the properties of graphene and dots,where the anomalous quantum Hall effect,Klein tunneling high transmissivity,high electron mobility and non-toxicity as well as the electronic and optical properties from have been retained.The graphene quantum dot is one of the new members in carbon alloytrops,and the quasiparticle in the dot obeys the Dirac equation,which bridges the gap between the condensed matter and high-energy physics.The electronic properties of the graphene quantum dot can be tuned by the external electric,magnetic fields dot size,based on which the thesis discusses the properties of the graphene quantum dots from the follwoing aspects:(1)Firstly,the energy-level structure of the graphene quantum dot with B = 0 in the quantum dots influenced by the magnetic barrier has been investigated.The effects of the different configurations of magnetic barrier on the energy-level structure have been explored,where the competition effect of the magnetic fields inside and outside the dots has been found and analyzed,elucidating the influence of the mass,magnegtic flux,and dot radius on the bound states of the system.In addition,the wavefunction of the bound states have also been calculated,showing the number of nodes,and ground and excited states in the magnetic barriers.(2)Then the scattering behavior of the Dirac particle tunneling through the graphene quantum dot driven by the electric and magnetic barriers has been studied by calculating the scattering efficiency and angulare current density.The resonance scattering and transient capture of the Dirac particle in the quantum dot computed by taking account of the electric and magnetic barriers,the incidence energy and dot size.The similarity and difference have been found in the three different cases,where the electric,magnetic and mass barriers have been discussed and compared in detail.