Terahertz radiation from the Dyakonov-Shur instability of hydrodynamic electrons in Corbino geometry

Hydrodynamic electrons flowing through a two-dimensional channel are predicted to undergo plasma instability above critical drift velocity. This Dyakonov-Shur (DS) terminates as coherent nonlinear oscillator, which shows promise source of radiation that could fill the so-called terahertz gap. In this work, we study radial flow in Corbino disk, and demonstrate how DS is substantially enhanced geometry, both terms lower velocity higher generated power. Interestingly, hydrodynamic electron flows were recently reported graphene sample our results therefore directly relevant current efforts detect experimentally elusive phenomenon. The analysis based on approach features linearized calculations well full numerical simulations Navier-Stokes equation.