Nonlinear electron dynamics in a resonant tunneling diode: Langevin-quantum-dynamics simulations on a massively parallel computer

A quantum-dynamics (QD) simulation scheme is developed to study highly nonlinear electron dynamics far from equilibrium. The time-dependent density functional theory is combined with the Langevin equation to incorporate quantum effects, electron-electron interaction, and dissipation. We perform QD simulations on a massively parallel computer to study the many-electron dynamics in a resonant tunneling diode. The dynamic response of electrons in n +-doped layers on the femtosecond scale is found to have a profound influence on the current-voltage (I-V) characteristic. The resulting time-averaged I-V characteristics are in excellent agreement with experiments.