The role of the Rashba coupling in spin current of monolayer gapped graphene

In the current work we have investigated the influence of the Rashba spin-orbit coupling on spin-current of a single layer gapped graphene. It was shown that the Rashba coupling has a considerable role in generation of the spin-current of vertical spins in mono-layer graphene. The behavior of the spin-current is determined by density of impurities. It was also shown that the spin-current of the system could increase by increasing the Rashba coupling strength and band-gap of the graphene and the sign of the spin-current could be controlled by the direction of the current-driving electric field

Magnetoresistance in Graphene-Based Ferromagnetic/ Rashba Barrier/Ferromagnetic Heterojunction

The quantum tunnelling of spin-polarized electrons through a Rashba barrier on a single layer graphene is studied by the scattering matrix method. It is shown that the magnetoresistance, defined as the difference between conductance at the presence and absence of the Rashba spin-orbit interaction, oscillates with the intensity of interaction. These oscillations are also observed in the conductance versus the potential energy of the barrier

Quantum transport of massless Dirac fermions through wormhole-shaped curved graphene in presence of constant axial magnetic flux

Abstract In this work, we have studied the spin-dependent quantum transport of charged fermion on $$(2+1)$$ ( 2 + 1 ) -dimensional spacetime, whose spatial part is described by a wormhole-type geometry in the presence of constant axial magnetic flux. Choosing the solutions of the Dirac equation associated with real energy and momentum, we explored the spin-dependent transmission probabilities and giant magnetoresistance (GMR) through a single layer of wormhole graphene with an external magnetic field, using the transition matrix (T-Matrix) approach. The spin-up and spin-down components within the A and B sublattices of graphene in the matrix of $$4\times 1$$ 4 × 1 wave function are coupled to each other due to the wormhole structure and the magnetic field. We have found that transport properties strongly depend on the magnetic field, incident energy, and geometric parameters of the system. We observed that the transmission probability increases as the radius of the wormhole increases, and the length of the wormhole decreases. The higher energies lead to a decrease in the transmission probabilities of particles. Furthermore, we observed that the probability of the spin-flip effect is almost larger than that of the non-spin-flip effect, illustrating that electrons lose their spins during transmission. These findings highlight the complex and interesting behavior of wormhole graphene in the presence of external magnetic fields and suggest that these nano structures can have potential applications in electronic and spintronic devices