Supported by NSF-PREM grant DMR-0611562

1. Approaching the intrinsic band gap in suspended high-mobility graphene nanoribbonsLuis Agapito and Nicholas KioussisCalifornia State University Northridge Electrical transport measurements on a suspendedultra-low-disorder graphene nanoribbon (GNR) with nearly atomically smooth edges have been carried out by Zhixian Zhou and co-workers at Wayne State University that reveal a high mobility exceeding 3000 cm2 V−1 s−1 and an intrinsic band gap. In collaboration with Efthimios Kaxiras, Harvard University, we have carried out tight-binding (TB) calculations in model GNRs of comparable width (∼20 nm) to elucidate the underlying electronic origin of the high band gap value in ultra-low-disorder GNRs. Calculated band gaps (black) and maximum spin magnetization (red) for various GNRs corresponding to chiral angles θ in ascending order Periodic unit cell used in the calculation is shown shaded in green. The zoom-in regions show the spatial distribution of spin-up (cyan) and spin-down (red) magnetization. The experimentally derived band gap is in quantitative agreement with results of our electronic structure calculations on chiral GNRs with comparable width taking into account the electron-electron interactions, indicating that the origin of the band gap in non-armchair GNRs is partially due to the magnetic zigzag edges. PHYSICAL REVIEW B 84, 125411 (2011) Supported by NSF-PREM grant DMR-0611562