Radius of effect in molecular quantum-dot cellular automata

Abstract

Molecular quantum-dot cellular automata (mQCA) is a promising technology for building molecular computers, where binary information is represented by the charge configuration within molecular redox centres. Molecular QCA devices are coupled by electric fields and no current flows in the circuits, in theory. The Coulomb forces, which cause electrons to move from one redox centre to another within a cell, may result in faults in neighbouring cells as well. A simple electrostatic model is presented that describes the interactions of double-dot molecules within an effective radius-of-effect (RoE). The proposed model can be applied to approximate the RoE in device simulation, as well as determining a reliable cell-spacing in mQCA circuits as to avoid faults. Compared with full quantum chemistry calculations, which are of high computational cost, this simple model provides a rapid and straightforward tool for application in reliable mQCA device and circuit design.