Nano Structure Of Electromagnetic Transport Simulation

Spintronics mainly research the spin degrees of freedom and the transport properties of electronspin,and use these features to make spintronic devices.Electronic spin has two states:one is thespin-up,another is spin-down.In this paper we use the quantum ballistic transport model to investigate the spin field-effecttransistor’s transport properties, this model using the non-equilibrium Green’s function (NEGF) andPoisson equations are solved self-consistently..Using this model, we investigate the transportproperties of the different material spin field effect transistor, and compare with different dopingstructure of the spin field effect transistor.The research work includes the following three parts.Firstly, it uses non-equilibrium Green’s function method to deduce the corresponding physicalthe Green’s function’s expression of half-metallic-ferromagnet/sillicon/half-metallic-ferromagnetfield effect transistors in the mode space. Through calculating the electrical properties of the silliconspin field effect transistors by the mode space method, it finds that as the device’s size is decrease,result the DIBL effect and hot carrier effects.Second aspects in order to reduce the DIBL effect and hot carrier effects,we incestigate thesilicon field-effect transistor by LDD and linear doping,and compared with the ordinary doping,andit finds the spin field-effect transistors of LDD and linear doping can suppress the short channeleffect effectively, have a better control ability of gate, have a lower leakage current optimize theperformance of the switching current ratio.Third aspects uses non-equilibrium Green’s function method to deduce the correspondingphysical the Green’s function’s expression of we investigate the structure offerromagnetic/grapheme nanoribbons/ferromagnetic’s spin transport properties of electrons, thegrapheme nanoribbons contains zigzag and armchair two kinds of different interfaces. Throughcalculating the electrical properties of the two kinds of different interfaces by the mode spacemethod. The results indicate that the atomic arrangement at the interface between the FM electronand the GF has a dominant effect on the electron conduction through the graphene-based magneticjunctions. The planar FM/GF/FM junction with zigzag interfaces exhibits a spin-valve effect withMR values as high as95%and negative differential resistance features for a single spin channel. Inthe case of armchair interface, both spin channels are in on state with low MR ratios. These factors suggest that the junction with zigzag interfaces is an interesting candidate for application in themagnetic memory cells and spintronic devices.