Electron Transport Properties And Tunneling Magnetoresistance In A Periodic Silicene Superlattice

Silicene,a close cousin of graphene,is a monolayer of silicon atoms densely packed into a two-dimensional honeycomb lattice.It has high carrier mobility and conductivity,which is similar to graphene.Unlike graphene,silicene has a strong spin-orbit coupling and the buckled structure,which leads to the electronic band gap and the band gap adjustable.Silicene has recently attracted enormous attention that causese widespread research.In this paper,we study the transport property and tunneling magnetoresistance of the normal and defect periodic silicene superlattices and periodic magnetic silicene superlattices.The main results obtained by using transfer matrix method are listed as following:(1)We studied the valley resolved conductance,spin polarization,valley polarization and tunneling magnetoresistance of different exchange splitting energies vary with energy and staggered potential in the normal and defect periodic silicene superlattices.With the increase of the energy,we found that Dirac point is located in the minimum of the valley resolved conductance in the normal silicene superlattice,and the defect one appears a defect peak at Dirac point.The spin polarization and tunneling magnetoresistance have a platform region which reaches to 100%.Also,we obtain the condition for observing the fully spin polarized current.With the increase of the staggered potential,the larger the exchange splitting energy,the more strongly increased spin polarization,valley polarization and tunneling magnetoresistance.The valley resolved conductance is sensitive dependent on the defect effect,and spin polarization,valley polarization and tunneling magnetoresistance is not sensitive to the defect effect.(2)We studied the spin and valley resolved conductance,valley resolved conductance,charge conductance,spin polarization,valley polarization and tunneling magnetoresistance vary with the barrier height,barrier width,staggered potential and exchange splitting energy in the periodic magnetic silicene superlattice.With the increase of the barrier height,we found that the valley resolved conductance,charge conductance,spin polarization,valley polarization and tunneling magnetoresistance show a typical quasi periodic oscillation.With the increase of the barrier width,the oscillation period of the valley resolved conductance,charge conductance,spin polarization,valley polarization and tunneling magnetoresistance becomes shorter,and the position of that shifts toward the low barrier.With the increase of the staggered potential,the spin polarization,valley polarization and tunneling magnetoresistance have a platform region which reaches to 100%.With the increase of the exchange splitting energy,the platform region of the spin and valley polarization for P configuration and tunneling magnetoresistance is obviously tunable.