Center for Functional Nanomaterials Seminar

A device architecture for computing with quantum dots, Quantum Cellular Automata, points to a new paradigm for computation that goes beyond the conventional semiconductor technology roadmap to achieve ultra low power consumption. The Quantum Cellular Automata scheme is based upon “cells” of tunnel coupled quantum dots and electrostatic interaction between adjacent cells to transmit binary information and perform computations. Efforts to fabricate Quantum Cellular Automata devices have so far been limited by the need for extreme cryogenic conditions and by the debilitating effects of stray charges. It is conceivable that fabrication on a smaller scale can circumvent these limitations. Here we demonstrate that single atoms in a solid state environment can serve as quantum dots and that such quantum dots can be controllably tunnel coupled to embody the building block of a Quantum Cellular Automata Cells. Such cells exhibit “selfbiasing” effect, that is, the electron occupation is set by cell geometry. The binary state of the cell may be controlled electrostatically. This cell operates at room temperature and is largely immune to stray charges that are more than 30 Angstroms away from the cell.