Realization of a GaAs/AlGaAs-based quantum cellular automata cell

We report on the experimental demonstration of a four-dot cell on a GaAs/AlGaAs substrate fabricated using electron beam lithographically defined gates. These surface metallic gates form a pair of double quantum dots, as well as a pair of quantum point contacts that act as non-invasive voltage probes. This device is used to realize a quantum cellular automata cell and, in further experiments, we employ it to investigate photon assisted tunneling. These results prove that the four-dot cell is a good building block candidate toward fulfilling the scalability DiVincezo criteria.