Exploring the write-in process in molecular quantum cellular automata: a combined modeling and first-principle approach. (15th July 2019)

• Record Type: Journal Article
• Authors: Santana-Bonilla, Alejandro; Medrano Sandonas, Leonardo; Gutierrez, Rafael; Cuniberti, Gianaurelio
• Is Part Of: Journal of physics. Volume 31:Number 40(2019)
• Publication Date: 2019-07-15
• Subjects: quantum cellular automata -- density functional tight binding (DFTB) -- charge transfer -- non-adiabatic coupling; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/ab29c1
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: The molecular quantum cellular automata paradigm (m-QCA) offers a promising alternative framework to current CMOS implementations. A crucial aspect for implementing this technology concerns the construction of a device which effectively controls intramolecular charge-transfer processes. Tentative experimental implementations have been developed in which a voltage drop is created generating the forces that drive a molecule into a logic state. However, important factors such as the electric field profile, its possible time-dependency and the influence of temperature in the overall success of charge-transfer are relevant issues to be considered in the design of a reliable device. In this work, we theoretically study the role played by these processes in the overall intramolecular charge-transfer process. We have used a Landau–Zener (LZ) model, where different time-dependent electric field profiles have been simulated. The results have been further corroborated employing density functional tight-binding method. The role played by the nuclear motions in the electron-transfer process has been investigated beyond the Born-Oppenheimer approximation by computing the effect of the external electric field in the behavior of the potential energy surface. Hence, we demonstrate that the intramolecular charge-transfer process is a direct consequence of the coherent LZ nonadiabatic tunneling and the hybridization of the diabatic vibronic states which effectively reduces the trapping of the itinerant electron at the donor group.