Calculation of high-field diffusivity by a many-particle Monte Carlo simulation including a complete band structure for GaAs

The electron diffusion coefficients of GaAs in the high-field regime ranging from 10 to 500 kV/cm have been calculated by a many-particle Monte Carlo simulation. The band-structure model in the simulation, calculated using the empirical pseudopotential method, includes the lowest two conduction bands and the full many-valley structure for each band. Our calculation shows that the diffusivity decreases drastically (by a factor of ≊30) as the field increases from 10 to 250 kV/cm and extremely low diffusion coefficients, 1.1 cm²/s for D₁ and 6.1 cm²/s for D_t, are obtained at ≊250 kV/cm for GaAs.