Unveiling Charge Dynamics in Molecular Field-Coupled Nanocomputing

Molecular Field-Coupled Nanocomputing (molFCN) emerges as a promising technology for addressing the challenges posed by CMOS scaling. In molFCN, the charge distribution of molecules encodes binary information. Properly arranging molecules in specific layouts produces wires and logic gates in which the information propagates by electrostatic intermolecular interaction with nearby molecules. Prior research offered promising insights into the static properties of information propagation within molFCN circuits, providing a theoretical description of the mechanism. However, the promising frequency-switching capabilities of molFCN still need to be validated. The frequency study of molecules is essential for ensuring the overall reliability of future molFCN devices. Consequently, this paper introduces a new methodology combining Density Functional Theory (DFT) and Real-Time Time-Dependent Density Functional Theory (RT-TDDFT) simulations for determining the maximum switching frequency of molFCN candidate molecules. We validate the methodology using the oxidized 1,4-diallyl butane molecule. Our findings demonstrate the possibility of achieving hundreds of gigahertz-level switching frequencies for the 1,4-diallyl butane. Moreover, the results report the nonlinear molecule behavior when subjected to electric field excitations above its charge-switching frequency limits. Overall, this work presents advances in addressing the time-domain modeling of molFCN candidate molecules, opening pathways for improving existing models for molFCN circuits.