Electronic Transport And Shot Noise In Thue-Morse Gapped Graphene Superlattice

More than ten years ago,it was discovered that graphene is a single layer of carbon atoms packed in a honeycomb lattice.The electronic properties of graphene can be controlled by different techniques,including strain,electric field,and magnetic field,which may lead to promising applications in nanoscale carbon-based electronics.Especially,the electronic structure and transport property of graphene can be essentially modified under a superlattice structure.In this paper,we have designed the sixth generation of the Thue-Morse gapped graphene superlattice(TMGGS)model.Using transfer matrix methods,we investigate the electronic transport properties and shot noise of the model under the modulation of an applied electric field or both electric and magnetic fields.The main results obtained are listed below:Firstly,we investigate the electronic transport properties and shot noise in the sixth generation of the TMGGS under the modulation of an applied electric field.The results indicate that the transmission coefficient in terms of the incident angle is displayed asymmetrically due to the interplay between the band gap and the applied bias.The position of the zero-averaged wave-number gap is insensitive to the band gap but highly dependent on the applied bias.At the case of normal incidence,the Klein tunneling appears very clearly.With increasing of the band gap,the Klein tunneling can be suppressed strongly while the Klein tunneling is invariant under the influence of the applied bias.The minimum value of the conductance and the peak value of Fano factor at the new Dirac point are sensitive to the band gap,and the Fermi energy corresponding to them is dependent on the applied bias.The conductance decreases with the applied bias oscillationally,while the Fano factor increases oscillationally with the applied bias.Secondly,we investigate the electronic transport properties and shot noise in the sixth generation of the TMGGS under the modulations of both electric and magnetic fields.The results indicate that with increasing the magnetic field strength,the transmission peaks shift left and the transmission is no longer symmetric about the incident angle.The position of the zero-averaged wave-number gap shifts toward the low-energy direction when the applied bias is not equal to zero.This is due to the fact that the applied bias causes a change of the electric-potential structure.With increasing of the band gap or the magnetic field strength,the Klein tunneling can be suppressed strongly while the Klein tunneling is invariant under the influence of the applied bias.In the case of zero band gap,the conductance shows a small peak in the vicinity of the new Dirac point,and the peak of Fano factor at the new Dirac point is split into two peaks.This is the result of the interplay between the applied bias and the magnetic field.With increasing of the applied bias,the conductance is sensitive to the band gap and the magnetic field strength,and the Fano factor is very close to the Poissonian value when the band gap or the magnetic field is relatively large.