Transport Properties Of Double-Barriers In Monolayer Transition Metal Dichalcogenides

Since the successful preparation of graphene,the attention to two-dimensional materials has continued to rise,and a large number of relevant scientist have invested in the research of these materials.In recent years,two-dimensional materials have become the front end of the scientific research field.Among of those,monolayer transition metal dichalcogenides(TMDCs)have become an important part of the two-dimensional material system.The lattice of monolayer TMDCs is similar to that of graphene.It has a regular hexagonal structure,which makes it have two inequality valleys in the first Brillouin zone(called K Valley and K' Valley).Valley generally refers to the highest or lowest point of the Bloch electronic energy band.Although the concept of energy valley was first proposed for the graphene system,the difference between the valleys is mainly due to the time-reversal symmetry breaking of the crystal structure itself.While graphene has time-reversed symmetry,it is necessary to break the inversion symmetry by other external means to obtain the valley-related properties.With the enrichment of two-dimensional materials,scientists succeeded in preparing monolayer TMDCs,and found they have no spatial inversion symmetry.This makes up for some of the shortcomings of graphene in valley electronics and has become the best platform for studying the related field of valley.The nature of monolayer TMDCs has drawn attention in the field of valley electronics.In this paper,based on the three-band tight-binding model,we use the Green's function method and periodic boundary conditions to study the monolayer TMDCs.The transport properties of monolayer TMDCs are explored and studied by freely controlling the parameters such as the width,intensity,and number of barriers and wells added to the scattering region.It can be easily found from the calculation results that the transport properties such as transmission coefficient,reflection coefficient,and valley polarization are closely related to the parameters of the wells and barriers.This shows that by controlling the gate voltage,the purpose of controlling the valley behavior can be achieved.The study of the transport properties of monolayer TMDCs provides new ideas.At the same time,in the calculation process,the phenomenon of double resonance peaks appears in the relationship between the transmission coefficient and the incident electron energy.This is a new phenomenon,Its causes and behaviors may provide a new starting point and direction for exploring the nature of transport and valley electronics.