First-principles Study On The Transport Properties Of T Graphene

Two-dimensional materials have attracted wide attention because of their unique properties and potential application values.Graphene is one of the most representative two-dimensional materials,which has excellent characteristics such as high strength,good toughness,high electron mobility and so on.And its excellent performance also drives people to explore more two-dimensional materials with better performance.Among them,the carbon allotrope of two-dimensional materials is one of the key directions of exploration and research.In this paper,the first-principles method is used to study the electron transport properties of T graphene,which is one of the carbon allotropes.The following conclusions are obtained.We calculate the phonon-limited electron mobility of planar T graphene.First,its phonon-limited electron mobility decreases with the rising temperature and the increasing electron density.Second,we observe a low-temperature behavior?_e?^-5.53and predict a high-temperature behavior?_e?^-1 above the Debye temperature.This implies a very high characteristic temperature T_BG°in planar T graphene.Last,but the most important,we get a much larger room-temperature electron mobility(2.78×10⁶cm²/Vs)than that of monolayer graphene(1.35×10⁵cm²/Vs)at the same carrier density.Then we study the transport properties of mirror symmetrical armchair T-graphene(ATGNR),and calculate the zero-bias transmission spectra and I-V curves of undoped ATGNR,and Si,P,N,B-doped ATGNR respectively.We observe the negative differential resistance effects.The band structure of ATGNR is calculated by adding magnetic field and electric field respectively.Landau level appears in the presence of a magnetic field perpendicular to the ATGNR plane.In addition,a band gap exists at the Fermi level even when the magnetic field is 6.57T which can be obtained experimentally.At this point,the transmission channel is completely closed.The Dirac point in the band structure disappears and the transmission channel is completely closed when the transverse electric field is up to 0.43 V/(?).We also increase the width of the ribbon,and the Dirac point still disappears at the electric field 0.43 V/(?).Therefore,the addition of magnetic field or electric field to the ATGNR can be used for switch or logic.