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

TL;DR

This study investigates how uniaxial strain affects the electronic band structure and quantum conductance of graphene nanoribbons, revealing strain-dependent transitions between insulating and conducting states.

Contribution

It provides a detailed analysis of strain effects on GNRs using Wannier functions, highlighting how strain direction and magnitude influence electronic properties and conductance.

Findings

Strain can induce insulator-to-conductor transitions in AGNRs.

Tensile strain in the x direction increases conductance near the Fermi level.

Transverse strain significantly affects quantum conductance, with tensile increasing and compressive initially decreasing it.

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.