Transient dynamics of double quantum dots coupled to two reservoirs

T. Fukadai, T. Sasamoto

Published 2017-04-11Version 1

We study time dependent property of double quantum dots coupled to two reservoirs using the non-equilibrium Green function method. For arbitrary time dependent bias, we derive an expression of the time-dependent electron density of a dot and the current between these dots in the wide band limit approximation. For the special case of a constant bias, we calculate the electron density and the current numerically. As a result, we find that these quantities oscillate and the number of crests in a single period of the current changes depending on the bias voltage. We also obtain an analytical expression of the relaxation time, which expresses how fast the system converges to its steady state. From the expression, we find out that the relaxation time becomes constant when the coupling strength between the dots are large enough in comparison with the difference of coupling strength between the dots and the reservoirs.