Electron Spin Transport Property In FM/N Silicene Superlattice Structures

We investigate charge,valley and spin transport in a normal/ferromagnetic/normal/ferromagnetic/normal(N/FM/N/FM/N)silicene junction.All of our work is focusing on providing a guiding to the design of future nano-electronical devices.Firstly,we briefly introduce the research background on silicene,the crystal geometric structure of silicene,and the Hamiltonian under low energy approxi-mation with considering electric and magnetic field.Secondly,starting from the effective hamiltonian,we study the band structure of electrons in the normal sil-icene and ferromagnetic silicene.Under considering an electron transport in a N/FM/N/FM/N structure,the transport property of electron in such a structure can be investigated.Finally,we show our theoritical results in Chapter ?,and some interesting conclusion can be drawn from these theoritical results.The re-sults show that,the spin-conductance,spin polarization and valley polarization are significantly affected by the length of ferromagnetic strip,the distance between two ferromagnetic strips,the strength of spin orbit coupling,the exchange field,the on-site potential difference and the Fermi energy.The electrons transport in such a N/FM/N/FM/N structure results in a series of oscillating,resonant and decay-ing behavior.These oscillating and resonant behavior arise from the interference between the propagating states and the bound states located in the ferromagnetic strip region.And the decaying is caused by the imaginary wave vector of electron dominating the propagating property through the structures.For the parallel structure,our theoretical results show that spin-filter or valley-filter can be realized in such a structure.It allows one spin or valley propagating through the structure but inhibits the other one.While for the antiparallel struc-ture,due to the chiral property,the tranmission of electrons propagating through the structures via the opposite spin or vally are equal,both the spin filtering and valley filtering behavior could not be found in such a system.