Switching Quantum Interference in Single‐Molecule Junctions by Mechanical Tuning

The charge transport through single‐molecule electronic devices can be controlled mechanically by changing the molecular geometrical configuration in situ, but the tunable conductance range is typically less than two orders of magnitude. Herein, we proposed a new mechanical tuning strategy to control the charge transport through the single‐molecule junctions via switching quantum interference patterns. By designing molecules with multiple anchoring groups, we switched the electron transport between the constructive quantum interference (CQI) pathway and the destructive quantum interference (DQI) pathway, and more than four orders of magnitude conductance variation can be achieved by shifting the electrodes in a range of about 0.6 nm, which is the highest conductance range ever achieved using mechanical tuning. Switching among different anchoring sites of single‐molecule junctions was achieved by mechanical tuning, leading to the control of the transmission pathway between the destructive quantum interference (DQI) and the constructive quantum interference (CQI) at the single‐molecule level, which provides a new strategy for designing molecular electromechanics devices.