Electromechanical Switching of a C60 Chain in a Nanogap

Electromechanical switching in fullerene C-60 nanochains,introduced in the device as a C-60 pyrrolidine tris-acid(CPTA) film, was realized in nanogap electrodes with & SIM;20 nmseparation. Unlike microscale C-60 channels, a conductiveC(60) chain spontaneously formed in the nanogap without electronbeam irradiation. The initial current flow was likely due to electronhopping through the CPTA molecules. A higher voltage generated a nonlinearcurrent and caused a rapid current step to drastically generate alarge current flow. A further high current generated a sudden currentreduction recognized as the negative differential resistance, suggestinga resistance state change from a low state to a high state. At thehigh-resistance state, a step-like current increase changed the nanochainconduction to the low-resistance state. The high- to low-resistancestate switching was reproducible, and a sequential input voltage executeda binary resistance switching operation at room temperature. Fromthe switching voltage and current values, the switching energy forthe C-60 chain in the nanogap was estimated to be approximatelyseveral milliwatts, most probably caused by the polymerization anddepolymerization of the conductive C-60 chain.

Automated summary

Electromechanical switching was achieved in fullerene C-60 nanochains using a C-60 pyrrolidine tris-acid(CPTA) film in nanogap electrodes. A conductive C(60) chain formed spontaneously in the nanogap without electron beam irradiation. The switching operation from a high-resistance state to a low-resistance state was reproducible and could be executed at room temperature.