Current switching by conformational change in a π-σ-π molecular wire

The switching behavior of a conformational molecular switch with a π (benzenethiol)-σ (bicyclopentane)-π (benzenethiol) architecture is investigated by quantum mechanical calculations. The model molecular-wire exhibits current switching between the planar and perpendicular orientations of the two π-electron moieties with respect to each other. The current in the planar orientation is found to be 64 nA for an operating potential difference of 2.5 V. The current modulation (ON/OFF ratio) between the two conformational states of the molecule is calculated to be more than 7 at a switching voltage of 2.5 V. The energy barrier between the molecular conformations corresponding to the ON and OFF states are tens of $k_{B}T$ at room temperature, suggesting that the two states would remain isolated under normal operating conditions