The Electronic Transport Efficiency Of A Graphene Charge Carrier Guider And An Aharanov–bohm Interferometer

As a new material,graphene has been attracting attention since it was made in 2004.Its unique hexagonal lattice structure gives it a series of novel physical and chemical properties.In addition,it exhibits some novel quantum characteristics,in terms of electronic transportation,which make it promising in information transmission.At present,gate voltage controlled graphene nanoribbons have been continuously studied as a channel for transporting electrons.The transmission of electrons is similar to the transmission of electromagnetic waves in an optical fiber,both of which follow Snell's law.By manipulating the applied electric field in different areas,it is possible to carry out high-efficiency transportation of electrons in a specific area.Besides,it can be used as a research model in other aspects,such as using the gate voltage to form a ring-shaped channel.Then,it is to study the Aharanov-Bhom(AB)effect in graphene.The AB effect is an important quantum interference effect,and scientists still pay attention to it now.In this paper,our work mainly uses the tight-binding approximation model and the Green's function method to theoretically simulate the transportation of graphene electron channels under gate voltage control.We firstly studied the transporting properties of gate voltage controlled two-terminal graphene electronic channels.The transport state of the electronic state in the channel is analyzed from the aspect of the energy valley.It was found that,in this device,the edge states would participate in conduction and make a conductivity value of 2ne~2/h.The entire transportation process is valley-reserved.After that,we studied the transporting properties of the four-terminal graphene electronic channel and AB effect.For this straight channel,the conductance value is quantized and the guider shows high effciency in the optical fiber regime.For an AB interferometer formed by the two channels,the quantized conductance occurs when there are a few modes in the channel.The local density of states(LDOS)inside the channel shows quantum scars when the scattering is strong.At low magnetic field,a periodical conductance oscillation appears.The conductance has a maximum value at zero magnetic feld in the absence of intravalley scattering.The mechanism was investigated by LDOS calculations and a toy model.