Gating of a three-leg molecule.

We study the use of a simple three-leg molecule, triphenylene, as a transistor. This configuration allows increased voltage gain to be achieved. We analyze control of the transport between electrodes attached to two of the legs by a gate closely coupled electrostatically to the third leg, using self-consistent density functional calculations. In spite of the close coupling, the maximum voltage gain was less than unity, and this was attributed to efficient screening of the internal potential due to polarization of the molecular states. The transistor current vs. voltage characteristics were able to be reproduced using a simple electrostatic model.