Low-Energy Field Generation by “Bremsstrahlung” and Cherenkov Effects in Graphene Nanoribbons

Understanding the mechanisms of charge-photon interaction in low-dimensional systems is a challenging numerical problem involving velocity/frequency constraints. We suggest that applying an in-plane transverse magnetic field to a two-dimensional nanoribbon, combined with an electric field along its longitudinal axis, leads to accelerated and reflected charges: global momentum conservation implies forward “braking” radiation (Bremsstrahlung). As a second instance, we consider the quantum Cherenkov effect as a possible explanation of the charge-photon interaction observed experimentally. The emission of surface plasmons from traveling electrons in graphene, mediated by charge-field interaction, is shown to provide in-plane electromagnetic radiation down to THz and mm-wave frequencies.