Topology-driven transport diversity in ZP-graphene nanoribbons: From near-ballistic conduction to negative differential resistance via edge termination engineering

We report a first-principles study of ZP-Graphene nanoribbons (ZPGNRs) with distinct hydrogen-passivated edge terminations using density functional theory combined with the nonequilibrium Green's function formalism. The parent ZP-Graphene lattice, composed of periodic five-, six-, and eight-membered carbon rings, gives rise to nanoribbons whose low-energy electronic structure is highly sensitive to the chemical nature of the edge sites. By comparing five terminations (ZPGNR-2H, ZPGNR-P, ZPGNR-3O, ZPGNR-OP, and ZPGNR-2P) we show that edge passivation strongly redistributes frontier states near the Fermi level and produces markedly different transport responses. ZPGNR-P and ZPGNR-3O exhibit the highest zero-bias conductance and near-ballistic transport, while ZPGNR-2H displays a clear negative differential resistance (NDR) window at finite bias. In contrast, ZPGNR-OP is weakly conducting at zero bias but becomes progressively activated under applied voltage, whereas ZPGNR-2P shows moderate current with smooth saturation. Eigenchannel analysis reveals that these behaviors originate from termination-dependent modulation of the dominant conduction pathway, rather than from contact mismatch. The results demonstrate that ZP-Graphene nanoribbons can support multiple device functionalities within the same carbon backbone simply by changing the edge termination, making them promising candidates for atomically precise carbon nanoelectronics. • Five edge terminations of ZP-Graphene nanoribbons yield three distinct transport classes • ZPGNR-P and ZPGNR-3O show near-ballistic transport with eigenchannel transmission T ≈ 1 • ZPGNR-2H displays a clear negative differential resistance window near 0.6 V • ZPGNR-OP evolves from nearly insulating to moderate conductor under applied bias • DFT/NEGF analysis links transport diversity to the mixed ring topology of ZP-Graphene