فهرست مطالب edris faizabadi

In this work, we theoretically investigate the spin dependent conductance and polarization in a Hexagonal graphene ring (HGR) with zigzag edges connected to three semi-infinite leads in the presence of a perpendicular magnetic flux and Rashba spin-orbit interaction (RSOI). Results are obtained using the tight-binding model within the non-equilibrium Green’s function formalism and suggest that in the absence of magnetic flux, for appropriate values of Rashba strength and energy of the incoming electrons; high spin-polarized conductances with opposite direction can be obtained for right up and right down leads, respectively. In this case, the system can act as a spin spliting device. In addition, it is found that by applying a magnetic flux to the central region of the HGR, it is possible to determine the magnitude and direction of polarization in output leads due to the time reversal breaking so, the system can be consider as a good candidate for the spintronic applications.

In this study based on Green’s function formalism, we explore some aspects of the spin-dependent properties of a triple-quantum-dot ring structure. In this structure, one of the quantum dots has been considered to be non- magnetic and the Rashba spin-orbit interaction is imposed locally on this dot while the two others can be magnetic. Besides, it can be controlled the interference of electron waves in the output leads by tuning the parameters containing on-site energy of quantum dots, the magnetic flux penetrating inside the ring, the magnetic moment of dots and the Rashba spin-orbit interaction. The optimum parameters may lead to perfect splitting and polarization and simulate the Stern-Gerlach aparateus.

Spin-dependent electronic transport in a single-layer zigzag phosphorene nanoribbon ZPNR in a ballistic regimen has been investigated by using the non-equilibrium Green´s function method combined with the Lopez Sancho technique.Our findings show that spin conduction can be adjusted by an external electric field applied via the gate and perpendicular to the conduction channel. In particular, we have achieved the conditions that this zigzag phosphorene channel can play as a spin converter. So that the input spin up beam, under certain conditions, turns out to be an output spin down beam, which is of great importance in spintronics.