One molecule, two states: Single molecular switch on metallic electrodes

Abstract The state‐of‐the‐art density functional theory (DFT) has become an essential tool for the investigation and development of molecular electronics at the electronic and atomic level. In this review paper, we show several typical examples to demonstrate that the DFT approaches, combined with nonequilibrium Green's function method, are able to design many prominent molecular switches—the most fundamental component in molecular electronics that can be utilized in information storage and logic gates. We mainly review the progress and important features of four remarkable switches with distinct transition mechanisms: (a) azobenzene‐like switches based on the cis–trans isomerization; (b) diarylethene‐like switches based on open‐closed transition; (c) porphyrin‐like switches based on tautomerizations; and (d) benzene‐like switches based on the physisorbed state and chemisorbed state. Special attentions have been paid on the molecular configuration, switching mechanism, and the role of van der Waals forces between the molecules and the metallic electrodes. We also summarize the avenues to effectively tailor the bistability, reversibility, and transport properties of these systems. This article is categorized under: Structure and Mechanism > Computational Materials Science Electronic Structure Theory > Density Functional Theory