Tuning the electronic properties of cove-edged graphene nanoribbons with external strain

Abstract Graphene nanoribbons (GNRs) have been regarded as promising materials for nanoelectronics and spintronics due to their unique electronic, magnetic, and topological properties. In particular, cove-edged GNRs (CGNRs) are found to exhibit semiconducting properties while the band gaps are tuned by the size of coves or the distance of the adjacent cove units. Here, we report that the external strain significantly modulates the electronic properties of B-N doped CGNRs in addition to the size of coves and the distance of the adjacent cove units. We find that B-N doped CGNRs display semiconducting behavior with variable bandgaps depending on the cove topology. The strain-induced changes in the atomic structures of CGNRs have significant implications for their mechanical and electronic properties. The structural deformation under strain, not only releases internal stress and maintains the stability of CGNRs (up to 40% strain), but also modulates the band gap obviously (band gap turns from 0.84 eV to 0 eV, meaning a semiconductor to metal transition). It is also found that the strain leads to the band inversion and band flattening in CGNRs, making them promising candidates for strain engineering. Our work investigates the mechanical response and electronic properties of GNRs under uniaxial stress, which paves the way for evaluating the feasibility and performance of GNR-based devices.