▎ 摘　　要

Microwave third-harmonic response of narrow graphene nanoribbons (GNRs) is studied by employing Boltzmann equation techniques. It is assumed that the GNRs are electron-doped by electrostatic gating. We predict gate-voltage-driven periodic quantum oscillations of the microwave third-harmonic output power from such GNRs, resulting from the confinement-induced quantization of the Dirac energy dispersion cones into a set of energy subbands at the bottom of which the electronic density of states exhibits the Van Hove square-root singularities. The oscillations are shown to have a large enough amplitude (similar to several tens of decibel-milliwatts) and should be observable in narrow GNRs of width similar to 10 nm even at room temperature.