Effect of external magnetic field on the instability of THz plasma waves in nanoscale graphene field-effect transistors

The instability of plasma waves in the channel of field-effect transistors will cause the electromagnetic waves with THz frequency. Based on a self-consistent quantum hydrodynamic model, the instability of THz plasmas waves in the channel of graphene field-effect transistors has been investigated with external magnetic field and quantum effects. We analyzed the influence of weak magnetic fields, quantum effects, device size, and temperature on the instability of plasma waves under asymmetric boundary conditions numerically. The results show that the magnetic fields, quantum effects, and the thickness of the dielectric layer between the gate and the channel can increase the radiation frequency. Additionally, we observed that increase in temperature leads to a decrease in both oscillation frequency and instability increment. The numerical results and accompanying images obtained from our simulations provide support for the above conclusions.