Dynamical response in an array of quantum-dot cells
C.-K. Wang, Irina I. Yakimenko, Igor V. Zozoulenko, Karl‐Fredrik Berggren · Journal of Applied Physics · 1998
The time-dependent behavior of quantum cellular automata (QCA), chains of quantum-dot cells, is examined. Each cell consists of four quantum dots on the four corners of a square and contains two electrons. Cells interact with nearby cells via Coulomb potentials. We study the time evolution of the polarization of the cells due to the switching of a driver cell for the particular cases of linear chains and L-shaped configurations. Two different approaches are discussed. In the first one dissipation is not considered. For this case numerical results demonstrate that adiabatic switching can be used to implement QCA only for chains of two cells. In the second approach we explicitly include energy dissipation processes in a phenomenological way and obtain the time evolution of the polarization of the cells due to the switching of the driver cell. Dissipation processes are found to give rise to satisfactory response characteristics. For the cases studied no metastable states are found.