Combined effect of oriented strain and external magnetic field on electrical properties of superlattice-graphene nanoribbons

Using the tight-binding model, electronic quantum transport properties of strained superlattice-graphene nanoribbons (SGNRs) attached to two semi-infinite metallic leads are studied in real space and numerically. Then, with the combination of mode space (MS) and renormalization methods, general analytical formulas for the conductance and energy band gap of the strained system are derived. The formulas are useful in studying the impact of slice-like defects and uniaxial strains on the electronic transport properties of the system as well as in reducing the computation time. The calculations are based on the Green's function method, in which the effects of uniaxial strains and the concentration of boron nitride (BN) slices as well as magnetic fields on the electrical conductance and the band gap of the armchair SGNR are studied. It is shown that the conductance of the system reduces with increasing BN concentration so a gap opens and its value increases. Both uniaxial strains and the BN impurities cause the metal-semiconductor phase transition, while the magnetic fields induce a periodic metal-semiconductor transition. The electronic transport properties of the systems can be controlled by tunable parameters such as the BN concentration, oriented strain and magnetic field.