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Open Access Nano Express

Quasi-classical modeling of molecular quantum-dot cellular automata multidriver gates

Ehsan Rahimi* and Shahram Mohammad Nejad

Author Affiliations

Nanoptronics Research Center, School of Electrical and Electronic Engineering, Iran University of Science and Technology, Tehran, 16844, Iran

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Nanoscale Research Letters 2012, 7:274  doi:10.1186/1556-276X-7-274

Published: 30 May 2012

Abstract

Molecular quantum-dot cellular automata (mQCA) has received considerable attention in nanoscience. Unlike the current-based molecular switches, where the digital data is represented by the on/off states of the switches, in mQCA devices, binary information is encoded in charge configuration within molecular redox centers. The mQCA paradigm allows high device density and ultra-low power consumption. Digital mQCA gates are the building blocks of circuits in this paradigm. Design and analysis of these gates require quantum chemical calculations, which are demanding in computer time and memory. Therefore, developing simple models to probe mQCA gates is of paramount importance. We derive a semi-classical model to study the steady-state output polarization of mQCA multidriver gates, directly from the two-state approximation in electron transfer theory. The accuracy and validity of this model are analyzed using full quantum chemistry calculations. A complete set of logic gates, including inverters and minority voters, are implemented to provide an appropriate test bench in the two-dot mQCA regime. We also briefly discuss how the QCADesigner tool could find its application in simulation of mQCA devices.

Keywords:
Electron transfer reactions; Molecular electronics; Molecular gates; Molecular quantum-dots; Quantum cellular automata