Number Of Magnetic Barriers Research Articles

Controllable spin-dependent transport in silicene superlattice

Based on the transfer-matrix method, we theoretically investigate the spin-dependent transport properties in magnetic silicene superlattice in the presence of extrinsic Rashba spin–orbit interaction (RSOI). It is found that the spin transmission probability and spin conductivities can be efficiently controlled by the number of magnetic barriers. As the number of magnetic barriers increases, spin conductivities strongly decrease, and reduce to zero in the large on-site potential difference between A and B sublattices (Δz) region. The results indicate that a magnetic silicene superlattice exhibits a remarkable wavevector-dependent spin filtering effect. Also, the magnetoresistance (MR) ratio exhibits an oscillatory behavior with the Fermi energy. The MR ratio can be tuned by the Fermi energy, number of magnetic barriers and extrinsic RSOI. Specifically, in the presence of magnetic field the spin polarization can be observed, and increases by increasing the magnetic field.

Shot noise in magnetic field modulated graphene superlattice

We investigate the shot noise properties in a monolayer graphene superlattice modulated by N parallel ferromagnets deposited on a dielectric layer. It is found that for the antiparallel magnetization configuration or when magnetic field is zero the new Dirac-like point appears in graphene superlattice. The transport is almost forbidden at this new Dirac-like point, and the Fano factor reaches its maximum value 1/3. In the parallel magnetization configuration as the number of magnetic barriers increases, the shot noise increases. In this case, the transmission can be blocked by the magnetic–electric barrier and the Fano factor approaches 1, which is dramatically distinguishable from that in antiparallel alignment. The results may be helpful to control the electron transport in graphene-based electronic devices.

Transport properties of two-dimensional electrons through multiple magnetic barriers

Transport properties of 2-dimensional electron system in a varying magnetic flied are investigated theoretically by a transfer matrix technique. The exact magnetic field profiles and the corresponding vector potentials are presented instead of simulated ones. The results show that several transmission domains are formed and each domain contains (N−1)-fold resonance splitting which fully depends on the number of magnetic barriers N. The computed conductance also exhibits rich transfer properties. Three peaks are observed in the low energy range. With the increasing of N, the conductance curves tend to coincide with each other as the tilting angle of magnetization relative to z direction equals to π/2, while the conductance curves shift downwards for other θ. All of our calculations reveal the important features of electron tunneling through multiple magnetic barriers.