Transport Properties Of Z-shaped Monolayer Transition Metal Dichalcogenides Nanoribbon

Since the successful stripping of graphene in 2004,there has been a surge of interest in the properties and synthesis of two-dimensional materials.Graphene-like materials have been used in many fields.Monolayer transition metal dichalcogenides(TMDCs)have attracted much attention due to their unique characteristics.The first is the lattice structure of monolayer TMDCs is also hexagonal honeycomb structure.Different from graphene,monolayer TMDCs has no time-reversal symmetry,which leads to two inequality spin-polarized K and K? valleys in the first Brillouin zone;the second is its considerable direct band gap,which makes up for the vacancy of graphene in valleytronic.In this paper,based on the three-band tight-binding model,the recursive Green's function is used to investigate the transport properties by adjusting the size of electrode area and scattering area of Z-shaped monolayer TMDCs nanoribbons.Then,the gate voltage is applied to the scattering region of Z-shaped monolayer TMDCs nanoribbons under different sizes,and the influence of various parameters on the transport properties of the device is investigated.The results show that the transmission coefficient,reflection coefficient and valley polarization can be affected by changing the size of the nanoribbons and applying different gate voltage to the scattering region in a certain range.At the same time,the influence of Fermi energy(which can be regarded as the energy of electron incident)on the transport properties of nanoribbons under different parameters is also calculated.It is proved that the valley degree of freedom can be controlled by applying external conditions,which proves the feasibility of manipulating valley and provides a new idea and direction for the development of valleytronic.