Investigation On Spin Transport Properties Of Z-shaped Molybdenum Disulfide Structure

Molybdenum disulfide?MoS₂?is a kind of two-dimensional nano material similar to graphene.Because of its excellent material properties,it is considered as an ideal material for the new generation of electronic devices.Compared with graphene and other two-dimensional materials,molybdenum disulfide materials have stronger spin properties,and its application in spin devices has become a research hotspot in recent years.In this paper,the tight binding approximation model and the recursive Green function method are used to study the spin transport properties of monolayer molybdenum disulfide nanoribbons and two different Z-shaped molybdenum disulfide transport structures.In this paper,the structure,preparation,material properties,application and research status of monolayer molybdenum disulfide in spin devices are introduced.Secondly,the theoretical basis and transport model of simulation in this paper are described,including the three bands tight binding model and spin transport theory.Finally,in the third and fourth chapter,the main work and research conclusions are introduced as follows:1.The spin transport properties of two kinds of MoS₂ ribbons are studied.From the energy band structure,it is found that the energy band of zigzag MoS₂ ribbon will spin apart,showing metallicity;the energy band of armchair MoS₂ ribbon will not spin apart,and there is a band gap.Then,we analyze the edge transmission paths of each band in the edge state transport model from the DOS distribution.Because the number of Mo and S atoms on the two edges of the armchair ribbon is equal,the electron will transport evenly on the two edges.The spin conductance of the two kinds of ribbons shows that there is no spin polarization of the two kinds of ribbons,in order to separate the spin energy bands and achieve spin polarization,we add a ferromagnetic field to the channels of all structures in this paper.The armchair ribbons achieve 100% spin polarization in a small energy range,but the zigzag MoS₂ ribbons have the largest spin polarization only 50%.2.To solve the problem of low spin polarizability of zigzag MoS₂ ribbon,we designed two kinds of Z-shaped MoS₂ transport structure.The spin transport properties of the two structures were described from energy band,spin conductance and spin electron local density of state.The results show that the two structures can achieve 100% spin polarizability in a large energy range.In addition,if the size of the two structures is too small,the spin polarizability will be reduced.