Research Article Theoretical Investigation of Design Methodology, Optimized Molecular Geometries, and Electronic Properties of Benzene- Based Single Molecular Switch with Metal Nanoelectrodes Rafsa Koyadeen Tharammal , 1 Anand Kumar, 2 A. R. Abdul Rajak, 1 and Vilas Haridas Gaidhane 1 1 Department of Electrical and Electronics Engineering, Birla Institute of Technology and Science Pilani, Dubai Campus, Dubai International Academic City, Dubai 345055, UAE 2 Engineering, Amity University Dubai, Dubai International Academic City, Dubai 345019, UAE Correspondence should be addressed to Rafsa Koyadeen Tharammal; rafsakoyadeent@gmail.com Received 23 April 2020; Revised 13 July 2020; Accepted 23 July 2020; Published 1 September 2020 Academic Editor: Hassan Karimi-Maleh Copyright © 2020 Rafsa Koyadeen Tharammal et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Understanding the electronic properties at the single molecular level is the first step in designing functional electronic devices using individual molecules. This paper proposes a simulation methodology for the design of a single molecular switch. A single molecular switch has two stable states that possess different chemical configurations. The methodology is implemented for 1,4-benzene dithiol (BDT) molecule with gold, silver, platinum, and palladium metal nanoelectrodes. The electronic properties of the designed metal- molecule-metal sandwich structure have been investigated using density functional theory (DFT) and Hartree-Fock (HF) method. It has been perceived that the DFT and HF values are slightly different as HF calculation does not include an electron-electron interaction term. Computation of the switching ratio gives the insight that BDT with gold has a high switching ratio of 0.88 compared with other three metal nanoelectrodes. Further, calculations of quantum chemical descriptors, analysis of the density of states (DOS) spectrum, and frontier molecular orbitals for both the stable states (i.e., ON and OFF state geometries) have been carried out. Exploring the band gap, ionization potential, and potential energy of two stable states reveals that the ON state molecule shows slightly higher conductivity and better stability than the OFF state molecule for every chosen electrode in this work. The proposed methodology for the single molecular switch design suggests an eclectic promise for the application of these new materials in novel single molecular nanodevices. 1. Introduction Future computational devices will feasibly consist of logic gates that are ultradense, ultrafast, and molecular-sized. Existing computational architectures trade off between com- putational speed and power [1–3]. To overcome the physical size scalability and fabrication cost of conventional semicon- ductor devices, molecular electronics has a predominant role. Molecular electronics utilizes electronics application at the molecular level [4]. Potential benefits include dramatically increased computational speed, miniaturization down to the size of atoms and molecules, and lower fabrication costs. Molecular scale electronics has made substantial progress in recent years and a variety of important theoretical and exper- imental insights have been investigated, which could have implications for the development of molecular devices instead of traditional complementary metal-oxide-semiconductor (CMOS) devices in the very near future [5–8]. Single- molecule electronics entails the integrated struggle of chem- ists, physicists, material scientists, and electronics engineers in both theoretical and experimental ways. Molecular elec- tronics or moletronics is the combination of molecules and electronics [9]. It is a multidisciplinary area that spans phys- ics, chemistry, material science, and electronics engineering [10]. This is a revolutionary concept even today when consid- ering the increasing device variability of CMOS technology Hindawi Journal of Nanomaterials Volume 2020, Article ID 6260735, 15 pages https://doi.org/10.1155/2020/6260735