Spin and orbital angular momentum transfer into GanAsn nanocage: The change in induced magnetic field by tuning the light parameters and size of the molecule

Abstract

In this study, we demonstrate that the direction of a photoinduced magnetic field in semiconductor nano-scale quantum dots (nanocages) can be changed by tuning the frequency and the light parameters. In the case of the spin angular momentum (SAM) transfer to ring-shaped GanAsn molecule, some electrons of occupied states are excited into the unoccupied states for a special laser frequency. As a result of the transition due to the circular polarized light, the excited electron which has a nonzero magnetic quantum number start to circulate around the molecular GaAs ring. The transfer of orbital angular momentum (OAM) due to the twisted light can induce similar effect on the molecular ring. In the case of twisted light, the electron can be excited different unoccupied states with higher magnetic quantum numbers. In the study, the optimization and electronic structure calculation have been performed by using density functional theory (DFT). The induced current and corresponding induced magnetic field can be controlled by the change in the frequency. Also, the type of the angular momentum of the light (SAM or OAM) can be used as a tool to manipulate the magnitude and direction of the magnetic moment.