Optical Atomic Switch utilizing a Molecular Junction

Abstract

Optical atomic switches have garnered considerable interest due to its fast switching speed, low energy consumption, and compatibility with quantum information technologies. While atomic modulation via optical excitation has been demonstrated using scanning probe techniques, controlling atomic motion in operable devices remains a key challenge for practical applications. In this study, we operated an optical atomic switch and investigated molecular effects on conductance modulation. Single-molecule junctions incorporating C 60 , bipyridine, and butanediamine were fabricated using a mechanically controllable break junction technique. Photoirradiation induced conductance enhancement in all molecular junctions. Analysis of current-voltage characteristics in ON and OFF states revealed that atomic motion modulates the electronic coupling between the molecule and electrodes. A systematic comparison across different molecular junctions showed that molecular rigidity significantly influences optical conductance modulation, with flexible molecules like butanediamine exhibiting weaker dependence on initial conductance states.