Programme

P.32 -- Poster, NCTP-43

Date: Tuesday, 31 July 2018

Time: 08:30 - 10:00

The trapping time of electron in an electrically induced circular graphene quantum dot

Nhung T. T. Nguyen

Institute of Physics, Vietnam Academy of Science and Technology, Hanoi, Vietnam

In graphene, electrons can only be trapped in a finite time due to the effect of the Klein tunneling. We study the trapping time of electron in a circular graphene quantum dot induced by an external Gaussian potential. The trapping times are calculated through a numerical determination of the quasi-bound states of electron in the quantum dot by solving the two-dimensional Dirac-Weyl equation. We show that the trapping time increases with the angular momentum m of electron. The trapping time depends on the dot radius differently for different m. In particular, the trapping time increases with the dot radius for m < 3 but decreases with the dot radius for m > 3. On the other hand, the trapping time always decreases with the potential height for every m. The calculated wave functions of the quasi-bound states show that an electron having longer trapping time is also better localized in space. Our results also indicate that there is a tradeoff between the capabilities of a graphene quantum dot to trap more electrons in the dot and to trap them more efficiently in time.

Presenter: Nguyen Thi Thuy Nhung