Strain effect on quantum conductance of graphene nanoribbons from maximally localized Wannier functions

Abstract: Density functional study of strain effects on the electronic band structure and transport prop- erties of the graphene nanoribbons (GNR) is presented. We apply a uniaxial strain in the x (nearest-neighbor) and y (second nearest-neighbor) directions, related to the deformation of zigzag and armchair edge GNRs (AGNR and ZGNR), respectively. We calculate the quantum conduc- tance and band structures of the GNR using the Wannier function in a strain range from -8% to +8% (minus and plus signs show compression and tensile strain). As strain increases, depending on the AGNR family type, the electrical conductivity changes from an insulator to a conductor. This is accompanied by a variation in the electron and hole effective masses. The compression x direction strain in ZGNR shifts some bands to below the Fermi level (Ef ) and the quantum conductance does not change, but the tensile x direction strain causes an increase in the quantum conductance to 10e2/h near the Ef . For transverse direction, it is very sensitive to strain and the tensile y direction strain causes an increase in the conductance while the compressive y direction strain decreases the conductance at first but increases later.