| The thermoelectric properties of low dimensional materials have become a hot research in condensed matter physics in recent years.Graphene nano device is a typical low dimensional system,which is influenced by the boundary,the width,the configuration and the external field,etc.This indicated that graphene nano devices will become one of the ideal candidate for low dimensional thermoelectric materials.And it should be sure that it is important to continue to explore the properties of graphene nano device which can be significantly improved.In recent years,the 5-5-8-type wire defect has been successfully constructed in graphene,which provides a new method for the quantum transport and transport in graphene and its nano devices.It can be predicted that graphene nano devices will exhibit many valuable thermoelectric properties due to the existence of linear defects.This paper intends to select several typical graphene nanodevices,discussed by the transport of a line defect modulated electron transport properties and comprehensive study line defect of the thermoelectric effect specific effects,and reveal the physical image.Through the study of this paper,we will summarize the regulation and control characteristic of the line defect of graphene nano electronic devices transport transport and thermoelectric properties,to define the key factors to improve the thermoelectric effect,and to keep a linear defects in the graphene nano devices model proposed to achieve high efficiency of thermoelectric conversion programs,provide strong support for the related experiments.This paper mainly launches the following two aspects of theoretical research.First,the 5-5-8 type wire defect is embedded in the Armchair and Zigzag graphene nano devices,which is composed of five two edge rings and a eight periodic ring of periodic intercourse.Because of the different width of the nano device,the electronic movement can show the rich physical phenomenon.We found in coupling graphite graphene quantum dot edge and line defect will increase in the conductance of the Dirac point value,also resulted in an increase of the conductance peaks,and will stabilize the original conductance peaks.However,if the coupling of different forms of the graphene quantum dot is present,two new conductance values will appear near the Dirac point.Thus,it is concluded that the existence of the midline defects in graphene QDs is of great significance for understanding the nature of electron transport.This is a worthy scholar to continue to study.Secondly,a new type of line defect is introduced.It is made up of MI,which is 5-5-8 type line defect and the following width is M2,which is embedded in the two kinds of structure of the 5-7-5 line defect.Because of the different width of Armchair graphene nano device,the electronic transport in the graphene nano device with the Armchair type graphene will generate different conductance values.The change of the width of Armchair graphene nano device will result in different conductance spectra values of MI.When the wire defect is embedded in the width of Armchair graphene nano device M=3n+2 graphene,the electronic transmission increased.The scattering of electrons by the wire defect will obviously inhibit the electron transport,and the conductance spectrum will also be reversed.If the M?3n+2 type graphene nano device is embedded in the width Armchair,the electron transport is attenuated and the conductance spectrum is increased.Finally,line defects influence the electron thermoelectric effect and Seebeck coefficient.The study found that,embedded mixed line defect makes the Seebeck coefficient increases the absolute value of the and thermoelectric effect optimal value also increases.Therefore,the appearance of the line defect is advantageous to the enhancement of the thermoelectric effect. |
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