Interparticle collisions and hot-electron velocity fluctuations in GaAs at 80 K

The microwave spectral density of longitudinal current fluctuations in silicon-doped n-type GaAs at 80 K at moderate electric fields $(<1$ kV/cm) is calculated. Electron collisions with phonons, impurities, and among themselves are taken into account by a modified Monte Carlo procedure. The important role of interelectron collisions is disclosed, and velocity-velocity cross correlation under nonequilibrium conditions is calculated. The quantitative fitting to the available experimental data on the spectral density of current fluctuations is achieved, and the range of fields is defined for interparticle collisions to manifest themselves in the noise.