Institute of Physics, VAST  Center for Theoretical Physics  Center for Computational Physics 
39th National Conference on Theoretical Physics (NCTP39)
Hội nghị Vật lý lý thuyết toàn quốc lần thứ 39
Buôn Ma Thuột, 2831/07/2014

ProgrammeConference PresentationO.10  Oral, NCTP39 Date: Tuesday, 29072014 Time: 14h20  14h40 FockDarwin energy spectrum of the gatetunable circular graphene quantum dotsNguyễn Thị Thùy Nhung (1), Bùi Thị Hạnh (1) (1) Theoretical and Computational Physics Department, Institute of Physics, VAST, 10 Dao Tan, Ba Dinh Distr., Hanoi 10000, Vietnam The energy spectrum of the gatetunable circular graphene quantum dots in a perpendicular magnetic field is systematically studied. To this end we suggest an alternative model of the Gaussian confinement potential with the strength $U_0$ describing the gate voltage and the typical halfwidth d measuring the dot radius. In the absence of magnetic fields it was shown that despite the Klein tunneling the Gaussian confinement potential can create the quasibound states (QBSs) in the sense that their lifetime is long enough for practical purposes. For a given dot, i.e. given $U_0$ and $d$, the larger the angular momentum m of the state the longer its lifetime becomes and, typically, the states with $m \ge 5$ could be well considered as quasibound. While the QBS lifetime increases as the dot radius reduces, it may be effectively turned by the gate voltage. In the presence of a magnetic field, calculations show the FockDarwin energy spectrum for the dots with different $d$ and $U_0$. In general, magnetic fields enhance the localization of QBSs, the field effects are however depending on not only the value of $m$ but also its sign. In particular, for QBSs with negative angular momenta, the magnetic field may induce the delocalizationlocalization transition. Presenter: Nguyễn Thị Thuỳ Nhung 
Institute of Physics, VAST

Center for Theoretical Physics 
Center for Computational Physics
© 2012 Center for Theoretical Physics & Center for Computational Physics Institute of Physics, VAST, 10 Dao Tan, Hanoi, Vietnam 