Spin filtering device through designing the normal/ferromagnetic/normal graphene superlattices

Abstract

Quantum transport properties of normal/ferromagnetic/normal graphene (NG/FG/NG) superlattices
exposed to ferromagnetic graphene connected to a gate electrode are investigated via the transfer
matrix method. Here, we calculate the role of parameters including well, and barrier width in
the spin current. In addition, the Fermi energy and gate voltage effects on raising and tunable
spin splitting have been investigated. Calculations demonstrate that the exchange field applied
to the region of the ferromagnetic graphene device, by changing the chemical potential, results
in an oscillatory behavior. We found that it opens a gap and indicates a metal-insulator phase
transition by enhancing unit cells (N = 100). Meanwhile, results reveal that by tuning the gate
voltage, we can control the spin currents, as a result, it may allow for the filtering of up or down
spins. Further, increasing the barrier width and Fermi energy reveals that the spin current is
reversible. Furthermore, this computational research found that quantum modulating behavior
by controlling wells, barrier widths, and chemical energy in the device. The results might have
potential applications in designing nano-devices and developing spintronic systems.