Transient Process of Transport Through a Quantum Dot in aStepped Bias: a Numerical Approach

The time evolution of current though a quantum dot responding to a stepped bias voltage is studied by a numerical approach in the mixed-valence regime and the Kondo regime. Our numerical results show the quasi-periodic oscillations of the current with a short damping time. When the deviation of the Fermi energy from the resonant dot level is increased by changing the gate voltage, the frequency of the oscillations is increased, but the average current decreases. The results also show a relatively slow oscillation in the Kondo regime.