The Gating Efficiency of Single-Molecule Transistors

Using self-consistent first principles calculations, we study the gating efficiency of fullerene-based single-molecule transistors. We find that the efficiency depends sensitively on the geometry of the gate electrode and on the contact coupling between the molecule and the source and drain electrodes. In particular, a 4-rectangles gate electrode that surrounds the junction is substantially more effective than a conventional single-rectangle gate electrode. As the coupling strength of the molecule to the source–drain electrode is reduced, the underlying molecular orbitals localize in space and are more readily shifted, giving rise to enhanced gating efficiency.