Current Induced and Thermal Switching of a Molecular Motor

Paul Yu Hsiang Yen¹, I-Chen Sang¹, Yi-Kai Huang¹, Rishi Raushan Bhardwaj¹, Hideki Okamaoto², Germar Hoffmann^1*

¹Department of Physics, NTHU, Taiwan
²Department of Chemistry, Okayama University, Okayama, Japan

* Presenter:Germar Hoffmann, email:germar.hoffmann@googlemail.com

Precise control over molecular functionality at surfaces is essential for the development of advanced nanoscale devices. Molecular bistability, characterized by the ability to switch between two stable configurations, offers a promising approach for creating mechanical switches at the single-molecule level. Such switching is successfully demonstrated for a range of molecules in local experiments [1]. However, our current understanding is obscured by the dominance of external control mechanisms in experimental realizations. These external factors, such as light, current, or potential, overshadow the subtle yet critical influence of the local environment on the potential barrier for switching and, respectively, on the tailored environment design for nanoscale devices

In this study, we investigate the structurally flexible ethane bridge of 1,2-bis-[1-phenanthryl]ethane on Ag(111) using scanning tunneling microscopy (STM)-induced manipulation. We observe both controlled switching via hot electron injection and thermally driven back-switching, governed by the Boltzmann distribution. By systematically studying the temperature-dependent back-switching behavior in various local environments, we gain unique insights into the underlying molecular interactions. We will discuss the results in terms of temperature and the interaction of molecules with its neighborhood.

[1] Review Article: “Towards single molecule switches”, Zhang et al., Chem. Soc. Rev., 2015, 44, 2998-3022

Keywords: Surface Science, Scanning Probe Microscopy, Molecular Adsorption, Bistability, Molecular Motor