A nano-mechanical device using a Ag₂S-C₆₀ system

Electronic circuit elements that show analog resistance change are required for the development of hardware-based machine learning systems. The energy level of a molecular orbital changes when the bond angle is distorted, for example when using a C₆₀ molecule that is compressed by a scanning tunneling microscope (STM). The issue for practical use of this phenomenon is how to compress a C₆₀ molecule in actual devices. In this study we have developed an electrochemical method in which Ag atoms precipitated from a Ag₂S electrode compress a C₆₀ molecule. We measured the I/V characteristics of a C₆₀ molecule using a STM equipped with a Ag₂S tip. The I/V characteristics clearly show the change in electronic states of the C₆₀ molecule due to compression by the precipitated Ag atoms. Since this method can be implemented in actual devices, a Ag₂S-C₆₀ system will be a candidate element for future machine learning systems.