Scientists at Empa and EPFL have identified a new type of defect as the most common source of disorder in on-surface synthesized graphene nanoribbons, a novel class of carbon-based materials that may prove extremely useful in next-generation electronic devices. The researchers identified the atomic structure of these so-called ''bite'' defects and investigated their effect on quantum electronic transport. These kinds of defective zigzag-edged nanoribbons may provide suitable platforms for certain applications in spintronics.