NUMERICAL STUDY OF THE CURRENT INSTABILITY IN A 2-DIMENSIONAL ELECTRON FLUID

Nonlinear evolution of the current instability in two-dimensional elec tron fluid is studied with the use of computer simulation. Recently it was found that this current instability may take place in a ballistic field-effect transistor. We show that the development of the instabil ity results in an establishment of stationary periodic oscillations ev erywhere over the investigated area of parameters. In the case of smal l increments, the oscillation amplitude is proportional to the square root of the increment and is well described by the analytical theory. For higher increments the growth of the amplitude slows down. In this case, the steplike distributions of electron concentration and velocit y, analogous to shock waves, are formed in the electron fluid. The dep endence of the frequency of oscillations on their amplitude is calcula ted.