Investigation Of Valley Resolved Transmission Through Gate Defined Graphene Carrier Guiders

In 2004,researchers had successfully made out of carbon allotropes of two-dimensional graphene in the laboratory.It has attracted great interest in the study.After years of research,scientists have found that graphene has unique physical and chemical properties and soon be-come one of the most important research topics in condensed matter physics.Graphene is also an ideal material for the study of valleytronics,due to its unique band structure.In this paper we study the transport properties of gate defined graphene carrier guiders.We use the tight binding model,the scattering matrix method to calculate the intervalley scattering coefficient of the graphene quantum potential well,including intervalley scattering coefficients and the intravalley scattering coefficients.We also analyze the properties of the conductance of the graphene carrier guiders under different conditions.We study the conductance variation and the intervalley scattering coefficients of the straight carrier guiders and the curved carrier guiders.Therefore,we have learned that for general straight carrier guiders,the quantized con-ductance platform value is(2n+1)2e~2/h and n is integer.Useing the energy band structure and wave function,we study the conductance variation and the intervalley scattering coefficients of the straight carrier guiders including different length,different relaxation width and different inclination angles.It is found that the intervalley scattering is very weak compared with the intravalley scattering.If we do not consider the influence of disorder,then the scattering be-tween the valleys occurs mainly at both ends of the quantum well and the scattering coefficient is very small.The conductance changes affected by different types of boundary and the change of conduction band direction.The above results do not depend on the degree of inclination or the edge shape of the graphene ribbon.For the curved carrier guiders,we have studied the conductance and the scattering coefficients of the valley with six different deformations.When the carrier guiders is bent into a cosine function,the quantized conductance is affected,and this depends on the shape of the band deformation.Meanwhile,we find that the scattering between the valleys remains very weak.What we did makes people aware of the conduction properties of valley resolved transmission through gate defined graphene carrier guiders,and understand the different variables influence on valley transport properties,which provide a the-oretical reference for further study on characteristics of valley transport in semiconductors,and can provide guidance for design of electronic devices in valleytronics.