Charging effects in the alternating-current conductance of a double-barrier resonant tunnelling structure

There have been many studies of the linear response ac conductance of a double-barrier resonant tunnelling structure. While these studies are important, they fail to self-consistently include the effect of time-dependent charge density in the well. In this paper, we calculate the ac conductance by including the effect of time-dependent charge density in the well in a self-consistent manner. The charge density in the well contributes to both the how of displacement currents and the time-dependent potential in the well. We find that including these effects can make a significant difference to the ac conductance, and that the total ac current is not equal to the average of non-self-consistently calculated conduction currents in the two contacts, an assumption often made. This is illustrated by comparing the results obtained with and without the effect of the time-dependent charge density included properly.