▎ 摘　　要

We report electrical transport measurements on a suspended ultra-low-disorder graphene nanoribbon (GNR) with nearly atomically smooth edges that reveal a high mobility exceeding 3000 cm(2) V-1 s(-1) and an intrinsic band gap. The experimentally derived band gap is in quantitative agreement with the 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 nonarmchair GNRs is partially due to the magnetic zigzag edges.