Effects of AB-flux and gap on magnetic graphene quantum dots

We consider magnetic graphene quantum dots (MGQDs) and study the impact of the Aharonov-Bohm (AB) flux and gap on the scattering process of electrons. Our emphasis is on the finite lifetimes of quasi-bound states arising from the interaction between electrons and the magnetic field within the dot. Initially, we calculate the scattering coefficients, scattering efficiency, and probability density by ensuring the continuity of eigenspinors at the boundary of MGQD. The results indicate that as the gap increases, the quasi-bound states reach higher maxima. We show that an increase in AB-flux leads to a generation of quasi-bound states requiring less magnetic field, and the scattering efficiency starts to take non-zero values at smaller MGQD sizes. The analysis of probability density shows that the quasi-bound states, corresponding to non-resonantly excited scattering modes, exhibit a significant improvement in the concentrated density at MGQD. The improvement is a result of reducing the diffraction phenomenon and suppressing the Klein effect through an increase in AB-flux and gap. This increases the probability of retaining the electron for a longer period of time.